Though Giant Bowser's size has stayed roughly the same across the franchise, the method used to enlarge him is inconsistent, though it almost always occurs with outside help and when Bowser is in a life-threatening situation. For example, in New Super Mario Bros. Wii, Magikoopa enlarges Bowser after he falls into lava.
Super Mario series
Super Mario Sunshine
Giant Bowser appears as the final boss of Super Mario Sunshine alongside Bowser Jr. Giant Bowser is first seen sitting in an enormous hot tub full of green water with Bowser Jr. and Princess Peach. Mario appears and is shocked to see Bowser so much larger than normal. Bowser then roars at Mario for ruining his "family vacation" and the battle begins.
Giant Bowser attacks by breathing streams of purple fire and shaking the hot tub to splash slime at Mario. Bowser Jr. assists by shooting Bullet Bills from his ship. To defeat them, Mario must use F.L.U.D.D.'s rocket nozzle to ground pound all five points of the star-shaped tub. Each time he does so, the point will fall apart and Mario must use the debris to make it back up to the tub's rim. After all five points are hit, the tub flips over, dumping everyone in it out.
Bowser is later seen returned to normal size sitting on top of the upside-down tub next to Bowser Jr. Guiltily, he starts to tell him that he lied about Peach being Junior's mother, but discovers that his son already knows. Junior then tells his father that he wants to fight Mario again one day, which improves Bowser's mood. He comments that the royal Koopa line is still strong, but suggests that they both rest a bit.
New Super Mario Bros. Wii
At the end of World 8-Bowser's Castle in New Super Mario Bros. Wii, Mario encounters Bowser on a bridge. Mario gets past Bowser and hits a ! Switch that destroys the bridge, sending Bowser plummeting into the lava below. Mario then turns his attention to what appears to be Princess Peach in a cage above. The "princess", however, reveals "herself" to be Magikoopa in disguise. Magikoopa proceeds to spread magic dust into the lava, which begins to rumble and boil. When nothing happens, Magikoopa looks quizzically at the lava, when Super Bowser bursts out of the pool, knocking Magikoopa away, and roars at Mario, initiating the final boss battle.
In order to defeat Super Bowser, Mario must make his way through a labyrinth, allowing Super Bowser's fireballs and claw swipes to destroy structures blocking his path. Some ? Blocks, Coins and Goombas appear in this section. Eventually, Mario will reach a new section composed of floating platform. A Propeller Mushroom may be collected at the beginning of the section. Bowser will use a new attack here, pounding the lava to send waves at Mario. Mario will soon reach another, larger switch, which sits below the real Princess Peach's cage. Hitting the switch will destroy the floor and cause Super Bowser to fall, thus defeating him and completing the game.
Super Mario Galaxy 2
Giant Bowser appears as the main antagonist of Super Mario Galaxy 2, in which he grows by means of eating Grand Stars. At the beginning of the game, he terrorizes Toad Town and kidnaps Princess Peach, taunts Mario by saying that he will have Peach bake him a huge cake, then flies into space to create his own galaxy at the center of the universe.
Giant Bowser is fought three times throughout the game. The first fight takes place in Bowser's Lava Lair, in the mission Bowser's Big Lava Power Party. Bowser is seen sitting on a large throne before he pulls Mario to a planetoid to fight. In battle, Giant Bowser will attempt to punch Mario, with the spot his fist will land marked by a light. Each time he punches, his fist will get temporarily stuck in the planet. He will also summon meteorites to smash into the planetoid. To defeat him, Mario must wait or Bowser to punch, causing any meteorites to rise and glow yellow. Mario can then jump onto one and ground pound it at Giant Bowser. After this is done twice, Bowser will get angry. The battle continues as before, but Giant Bowser now uses a new attack, breathing fire around the planet. After he is hit twice more, for a total of four hits, Giant Bowser coughs up a Grand Star and shrinks down to normal size. Bowser allows a few moments to taunt Mario before teleporting away.
The second fight is in Bowser's Gravity Gauntlet in the mission Breaking into Bowser's Castle. At first, Bowser is nowhere to be seen, but surprises Mario and starts the battle. The fight is mostly the same, but there are new effects to each of Giant Bowser's attacks. His punches and meteor strikes create purple shockwaves, while his fire leaves a trail of flame. He is defeated in the same manner as before, once again shrinking and leaving behind a Grand Star.
The final battle is in Bowser's Galaxy Generator in the mission Bowser's Fortified Fortress. Bowser tells Mario his plan to create a new galaxy using pieces of the existing one and ruling it with Peach as his empress. He then fights Mario again. The battle is the same as the last, but Bowser's fist now releases six lasers that shoot across the planet. After two hits, this really makes Bowser angry, and this time, whenever he punches, it gives off eight lasers instead of six. After he is hit four times total with meteorites, he spits out the Grand Star and falls into the depths of the generator. However, just as Mario is about to collect the star, Bowser reappears, enlarged once again, and eats the Grand Star, and enlarges himself to around double the size than before. He then warps Mario into a planet-less area with a black hole in the background. The only thing for Mario to stand on is several meteorites. Bowser will fly closer and closer to Mario, punching him when he is close enough. Mario must launch meteorites at him when he is out of his shell. After four hits, Bowser laments his defeat and the fact that he never got to try a huge cake, before being sucked into the black hole.
During the credits, Bowser is found unconscious, much tinier than usual. Mario can attack him to make him angry, but Bowser can do nothing to Mario.
New Super Mario Bros. 2
At the end of World 6-Bowser Castle in New Super Mario Bros. 2, Mario meets Bowser and defeats him in much the same manner as the previous game. After Bowser's defeat, Princess Peach's cage, situated above the switch that destroys Bowser's bridge, is pulled up higher into the castle by its chain. Mario follows via floating platforms and encounters the Koopalings, who use their wands to enlarge Bowser in much the same manner as Kamek, even being knocked away when Super Bowser appears.
In this battle, Super Bowser attacks Mario from the background. Mario must make his way upward using floating platforms, which are initially moving upward, but then fall when he touches them. Super Bowser will destroy platforms with claw swipes. Mario must continue moving upward while dodging the swipes.
At two intervals, Mario will come to a floor where he must dodge streams of fire from Super Bowser until more platforms appear. Later in the battle, statues of Bowser's head will breathe fireballs to hinder Mario. Purple fireballs will home in on Mario. Eventually, Mario will reach a final floor where Princess Peach is found suspended over a switch that will defeat Super Bowser in the same way as the previous game.
Dry Bowser's boss fight in World Star-Castle works the exact same way, except his fireballs are blue and is much faster than Bowser.
New Super Mario Bros. U / New Super Luigi U / New Super Mario Bros. U Deluxe
Giant Bowser appears once again as the final boss in New Super Mario Bros. U. After Bowser is defeated in the final level, Mario runs outside the castle and Bowser Jr. flies in with the Junior Clown Car, carrying an unconscious Magikoopa. Bowser Jr. wakes Magikoopa and the two have a brief argument, ending with Magikoopa being convinced to enlarge Bowser again.
Outside, Mario spots Princess Peach trapped in a tower room. She waves to him, but a door with Bowser Jr.'s emblem slams in her face. Bowser Jr. then appears to taunt Mario before Giant Bowser leaps up and roars. During the battle, Giant Bowser will breathe fireballs, which take three hits from ice balls to destroy, stomp his foot to crush Mario, and jump. Bowser Jr. fights alongside him in the Clown Car, throwing Bob-ombs and ground pounding.
To defeat Giant Bowser, Mario must stomp Bowser Jr. and steal the Junior Clown Car. He must then fly directly above Giant Bowser by rapidly tapping the jump button and ground pounding on his head by spinning. While Mario is in the air, Bowser will attack by breathing up to five fireballs at a time, as well as streams of fire and claw swipes. Being hit will knock Mario out of the Clown Car, but not deal damage. After each hit, Bowser will curl into his shell and spin around the battlefield, making frequent jumps. After the shell spin, Bowser will breathe lava into the air to send fireballs raining down. Mario can also attack him by jumping on Bowser Jr. when he is running back to Clown Car to lob his shell at Giant Bowser, hurling fireballs, or throwing Bowser Jr.'s Bob-ombs at him.
After three hits from the Clown Car, 180 fireballs, or 90 hits from Bowser Jr. and/or Bob-ombs, Giant Bowser becomes dazed and lets out one last roar in defeat before going unconscious and falling off the battlefield. Bowser Jr. follows.
Mario Party series
Mario Party 5
Giant Bowser appears as the second stage of Bowser's boss minigame, Frightmare. After the player defeats Bowser by tricking him into ground pounding through the floor, the entire floor falls apart beneath them and they plummet to another boss stage. Bowser then drinks an elixir that transforms him into Giant Bowser. Unfortunately, his weight breaks the floor underneath him and he is forced to hang on to the edge of the stage.
During the fight, Giant Bowser will toss large red orbs that explode, leaving behind a smaller black orb. He will then breathe a stream of fire. The player must get him to hit an orb with his fire, turning it white. They can then pick it up and throw it at him. After the fire attack, Giant Bowser tosses a purple orb that sends a shockwave across the stage, requiring the player to avoid it before they throw the white orb. Giant Bowser will toss more red orbs each time he is hit. After he is hit five times, The black hole in the background sucks Bowser in.
Mario Party 9
Giant Bowser appears as the final boss of Mario Party 9, in the minigame Bowser's Block Battle. Players attack by rolling dice with their own face and Bowser's emblem on them. They are able to pick up and throw the dice repeatedly for 10 seconds. After the 10 seconds are up, dice showing players' faces are converted into energy balls that the players use to attack Bowser, gaining one point per hit, while Giant Bowser shoots three fireballs for each die showing his emblem, deducting a point from any player hit.
Once his health drops below half, Giant Bowser grows even larger and the second phase of the fight begins. Giant Bowser will now tilt the platform the players are on to add chaos to their rolls. After each set of rolls, Bowser will pull out a spiked dice block with images of the previous bosses on it and roll it. The die transforms into whatever boss is rolled and will perform a brief attack.
After Giant Bowser's health is depleted, he is launched into the black hole in the background and explodes, releasing several Mini Stars.
Mario Party 10
In Bowser's Boss Minigame Bowser's Tank Terror, after being shot by enough cannonballs from the tanks, Bowser falls into the lava, only for himself to reemerge as an enlarged Dry Bowser, who is roughly the same size as Giant Bowser.
Super Princess Peach
Giant Bowser (known in-game as Bowser 2) appears as the last stage of the final boss battle of Super Princess Peach. After being defeated once, Bowser uses the Vibe Scepter to enlarge himself and fights Peach on what appears to be the castle roof. He attacks by slamming his hands, causing spiky balls to fall, breathing fire, and creating rings of hammers that fly outward. When he slams down both hands, several Bob-ombs will fall. Peach must pick these up and throw them at Giant Bowser's face.
When Giant Bowser's health is reduced to three points, he starts breathing two fireballs at once. When it drops to two, he breathes a stream of fire. When he has only one health point left, he uses the Calm vibe to restore health. Peach must attack him repeatedly to wake him up so she can deal the final blow.
Yoshi's Island DS
Giant Bowser appears as the final boss of Yoshi's Island DS. After he is defeated in the level At Last, Bowser's Castle!, Bowser is enlarged by Kamek. Four differently-colored Yoshis battle him at once with the assistance of Baby Mario, Baby Peach, Baby Donkey Kong and Baby Wario.
Giant Bowser attacks from the background. He will attack by breathing fireballs and dropping rocks on the Yoshis. To defeat him, the team must collect Giant Eggs from Item Balloons floating by and throw all of them at Giant Bowser at once. He is defeated after six hits. After his defeat, Bowser shrinks down to his normal size and is carried away by three Toadies, on Kamek's orders.
Yoshi's New Island
In Yoshi's New Island, Bowser appears as the hidden final boss, traveling through time to attack Yoshi in his past. He appears in the secret level Make Way for King Bowser!, unlocked after all levels are completed without Flutter Wings. Bowser is dispatched by Yoshi, but Kamek retaliates by enlarging him with his hammer. He is battled in a similar manner to giant Baby Bowser, attacking from the background. He can breathe fireballs into the air, which rain back down, and summon Mega Guys. Kamek will also assist him by casting magic balls at Yoshi.
To defeat Giant Bowser, Yoshi must swallow a Mega Guy, turning it into a Mega Eggdozer, and throw the giant egg at Bowser while he is breathing fire, as he will block the attack otherwise. After each hit, Giant Bowser will slam the ground, causing section of the ground to move up and down, possibly sinking into the lava and making the battlefield uneven.
After being hit three times, Giant Bowser shrinks out of view and a glowing light emerges from where he shrunk and flies into the distance, apparently Bowser himself flying to his home time.
Mario & Luigi series
Mario & Luigi: Bowser's Inside Story / Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey
In Mario & Luigi: Bowser's Inside Story and its 3DS remake, Mario & Luigi: Bowser's Inside Story + Bowser Jr.'s Journey, Giant Bowser is a playable character, who is only used during giant battles. When he is crushed, Mario and Luigi must go to the Rump Command, where they play a minigame to spike Bowser's adrenaline. Once this is done, Bowser will grow large enough to fight whatever is threatening him. The first time this happens, Bowser attempts to fire a Banzai Bill at his castle, but the castle activates rockets installed by Fawful and lands on top of Bowser. However, he grows giant and lifts the castle up. He then fights it as a boss. Later, he is exploring Blubble Lake when he comes across a large propeller, belonging to the Tower of Yikk. After he activates the propeller by sneezing, the tower comes to life and stomps on him. Bowser is enlarged once again to fight it. Later he must battle the Fawful Express at Bowser Castle (which runs Bowser over) and a robotic, "Fawfulized" version of Peach's Castle called Super Peach's Castle of Fury (which crushes Bowser).
At a few points in the game, Bowser requests that he be enlarged, only to be reminded that it only works in mortal danger.
Giant Bowser has the same role in main story of the game's remake, with the addition of a giant battle mode in the Gauntlet of the Challenge Node, which involves Bowser re-fighting the previously defeated giant bosses, except they are much stronger and harder to beat. This form also briefly appears in the Bowser Jr.'s Journey side story, specifically the instance that appeared during the Tower of Yikk boss fight. This also nearly endangered Bowser Jr., Lemmy, and Larry of the Koopalings. Bowser Jr. also speculated that this form was what Starlow alluded to when she said that his father Bowser was "working hard".
During giant battles, the handheld device is held sideways, with Bowser to the left (right in the remake) on the Touch Screen and the boss on the other screen, opposite of what screen Bowser is on. All of Giant Bowser's attacks are executed with the stylus or mic (in the original game).
Mario & Luigi: Dream Team
Giant Bowser (simply called Bowser in-game) reappears in Mario & Luigi: Dream Team as the final giant boss of the game. He is faced in Neo Bowser Castle's dream world, where Bowser's dream self attempts to reach this form by eating a large amount of meat brought to him by his minions. However, when he learns that there is no more meat, he flies into a rage and begins devouring the scenery in an effort to grow even larger; when that fails, he leaps off a cliff and seemingly to his doom. However, just as Mario and Dreamy Luigi prepare to celebrate, Bowser returns in his full giant form, having used the adrenaline of the near-fatal fall to attain his Giant form (similar to how he grew in Bowser's Inside Story). After he knocks the Mario Bros. down to a lower level, he gloats that he fears nothing in his dreams; in response, Dreamy Luigi grows into Giant Luigi to fight Giant Bowser on equal terms.
In addition to the above-mentioned growth method, Bowser references Bowser's Inside Story by claiming that Luigi is copying him in becoming giant. He also begins the battle proper by yelling "SHOWTIME!", referencing his battle cry from the aforementioned game.
The battle with Bowser takes place on a long, metal bridge. At the start of each turn, Shy Guy Airtubs will blast away part of the bridge behind Giant Luigi. He will fall into the lava if they blast away the part he is standing on, taking significant damage in the process; to avoid this, he should keep moving ahead by hitting Bowser with a Hammer Uppercut to force him back.
Giant Luigi's attacks do little damage to Giant Bowser, so he should try to knock his foe into the lava for much more considerable damage. The easiest way to do so is to use a Hammer Chop to smack Bowser off the side of the bridge; however, Bowser will summon Airtubs to pull up a sturdy wall beside the bridge on subsequent turns to prevent Luigi from repeating the trick. The bridge also has some metal grates along its length; if Bowser is standing on a grate when Luigi's turn comes up, the Bros. can use a Jump or a Drill Stomp to break the grate and drop Bowser into the lava below. When Bowser reaches the end of the bridge, he will jump to a new location and change his tactics.
Due to his boss status, Giant Bowser has a wider variety of attacks compared to his appearance in Mario & Luigi: Bowser's Inside Story; however, he will only use each one during specific parts of the battle. Initially, he attacks by grabbing Giant Luigi and attempting to throw him into the lava behind him; Dreamy Luigi must first flail free of Bowser's grip, then overpower his following attempt to push him off the bridge. Success will push Bowser back, but he will quickly recover and charge at Giant Luigi instead; this is dodged by sliding to the opposite side of the bridge that Bowser is approaching from; if successful, Bowser will fall into the lava and take damage.
In the second phase of the battle (after the combatants jump to a new bridge), Giant Bowser will breathe a stream of fire at Giant Luigi. Giant Luigi must slide up to jump away from the flames and grab onto a passing Airtub. He will swing back and forth towards Bowser and then towards the lava; since Bowser will slowly raise his flames to hit Luigi, the player must tap the screen when he swings towards Bowser to land on his head and dodge the flames. If Bowser is standing on a grate when this happens, the jump will break it as normal.
At the end of each bridge, Giant Bowser will hide behind a large fort and send his minions to attack Giant Luigi in a random order.
At the end of the "minion attacks", Giant Bowser will jump onto the fort and try to body slam Giant Dreamy Luigi; this is dodged by sliding back at the last moment. If successful, Bowser will collapse on the ground in a dazed state, allowing Giant Luigi to pick him up by the tail and swing him around (reminiscent of Super Mario 64) by repeatedly sliding the stylus. After spinning for a while, Giant Luigi throws Bowser into the fort to destroy it and damage him; if he builds enough momentum, he will end up tossing Bowser right into the lava for even more damage.
After being cornered at the end of the second bridge, Giant Bowser will jump to an circular arena, with Giant Luigi following. This time, Bowser will retreat into his shell and charge at Giant Luigi, who spins around with his hammer to counter. The player must tilt the Nintendo 3DS to control Giant Luigi's movements and "Repel the Shell" by knocking Bowser into the lava. The arena has several walls and forts that can be broken by either Luigi or Bowser, but the impact will bounce back whoever hits them. Each time Bowser falls into the lava, a giant Mushroom may fall in the center of the arena; Giant Luigi can touch them to restore his health, but so can Giant Bowser.
After being knocked into the lava enough times, Giant Bowser becomes vulnerable to the Finishing Bros. attack, seemingly putting an end to the fight. However, Kamek will return with one last trick up his sleeve; with the help of other Magikoopas, he fully heals Giant Bowser while making him grow to a size that dwarfs Giant Luigi. For this final phase of the battle, Bowser can use one of two moves: a colossal fireball or a stomp attack. The fireball is countered by tapping it repeatedly as Luigi struggles to hold it back with his Hammer; this is similar to how he countered the Robo-Drilldigger's energy ball, but made more difficult by the fireball moving around the screen. If Giant Bowser tries to stomp on Giant Luigi, the player must repeatedly tap the two arrows that appear to let Giant Luigi lift the foot off of himself; since each arrow corresponds to one of Giant Luigi's arms, the player must evenly distribute their taps to prevent him from being crushed. Countering either attack will knock Giant Bowser into the lava, allowing the Mario Bros. and Prince Dreambert to use the Star Driver to finish him off once and for all.
In Hard Mode, Giant Luigi takes more damage from Giant Bowser's attacks and no Mushrooms appear during the "Repel the Shell" stage. During the minion attack phases, the Airtubs fire more cannonballs and there will be two platoons of Spear Guys attempting to swarm Giant Luigi in each phase. In the final phase, Giant Bowser will lead off with his stomp attack instead of the huge fireball.
Like the other giant bosses, Giant Bowser has a counterpart in the Battle Ring, called Bowser X. While his strategy is mostly unchanged, he has higher stats and moves faster; the turn limit also forces Giant Luigi to make the most of every attack opportunity in order to defeat Giant Bowser in time.
Paper Mario: Sticker Star
Giant Bowser (known in-game as Bowser) appears as a final boss once again in Paper Mario: Sticker Star. After being defeated in Bowser's Sky Castle, Bowser plummets off the edge of a cliff, but reemerges as a giant, cardboard version of himself. In this state, he attacks by slamming one of his hands onto Mario, slamming both hands multiple times, or by swatting him. The former two attacks deal 10 damage, the latter deals 4 damage three times followed 8 damage, for a total of 20, and all three attacks and can induce the Crumpled status effect.
Bowser's Royal Sticker prevents him being harmed by Jump attacks or being hurt very much at all. To counter this, Mario's partner Kersti turns herself into a sticker for Mario's use. She causes the battle spinner to always match three images (of her face), healing 20 HP, allowing Mario to use five stickers per turn, and making him shiny, allowing him to deal a normal amount of damage to Giant Bowser.
When Giant Bowser has taken enough damage, he attempts to attack, but his arm falls off. At this point he attacks by breathing fire, dealing 15 damage and possibly burning some of Mario's stickers, and ground pounding to cause rocks to fall, dealing 10 damage.
After his HP is depleted, Giant Bowser returns to normal and loses his Royal Sticker.
Super Mario Sunshine
Super Mario Galaxy 2
Mario & Luigi: Bowser's Inside Story
Mario & Luigi: Dream Team
Paper Mario: Sticker Star
Mario & Luigi: Dream Team
Names in other languages