Fireworks are explosives that can be found in many Mario games dating back to Super Mario Bros.
At the end of every level in Super Mario Bros., with the exception of a castle level, fireworks go off when Mario or Luigi enters the tiny castle if the last number in the timer when hitting the flagpole is a 1, 3, or 6. If the last number is 1, one firework goes off; if the last number is 3, three fireworks go off and so forth. Each explosion awards the player with 500 points.
Fireworks appear again in Super Mario Bros.: The Lost Levels. Their method of appearing and function are exactly the same as they are in Super Mario Bros., awarding the player with the exact same amount of points.
In Super Mario World, fireworks are seen in the end of the game, after Mario rescues Princess Peach from the clutches of Bowser once again. Four fireworks shoot from the background, the last one being heart-shaped.
In Super Mario Bros. Deluxe, fireworks are seen at the end of the same levels as in the original NES version. However, when the player beats the game, a picture of Mario making a "peace sign" in front of a castle shows fireworks in its background.
In New Super Mario Bros., fireworks were once again used as a fairly common feature of the game. When the remaining time ended in 11, 22, 33, 44, 55, 66, 77, 88, or 99, Fireworks would go off behind the castle, with 11 setting off one firework, 22 setting off two, and so on. The original "Level complete" noise would play, and a Mega Mushroom house would appear if it ends in 77, 88, or 99, a 1-Up house for 66, 55, or 44, and an item house for 33, 22, or 11. They are only for one use, however. Fireworks are worth 4,000 points each in this game.
In New Super Mario Bros. Wii, fireworks are triggered depending on if the game is being played in single-player or multiplayer. In single-player, Mario has to successfully bring a red-capped Toad to the flagpole. The last digit of the remaining time told how many fireworks would be set off. In multiplayer, all players had to reach the flagpole when the last two digits of the timer were the same. The number of fireworks was determined by the numbers the last two digits were. In both modes, a Toad House would appear at the beginning of the world depending on the number of fireworks set off. A 1-Up Blast house would appear if one or two exploded, a Power-Up Panels house for three through eight, and a Star house for nine. Again, each one is worth 4,000 points.
In Super Mario Galaxy 2, the fireworks appeared at the end of the credits. During the last scene of the credits, the gang decided to watch the fireworks while Princess Peach baked a cake for Mario and Yoshi for saving the galaxy and defeating Bowser.
Fireworks also appeared during the game Super Mario 3D World. The number on the digit on the Time Limit determines how many fireworks the player received at the end of the course (one, three, or six), and which color the character is playing (red for Mario, green for Luigi, pink for Peach, blue for Blue Toad, and cyan for Rosalina). Each one adds 1,000 points to the player's score. Fireworks also appeared at the end of the final battle against Meowser in The Great Tower of Bowser Land. When he is defeated, he'll receive his very own firework, which resembles his head. It also appeared in the game's opening.
In Super Mario RPG: Legend of the Seven Stars Fireworks are an item obtained from a Mole Man in Moleville for 500 Coins. They can be traded in for the Shiny Stone in the same town. If Mario purchases one, the fireworks display at the end of the game will be Mushroom-shaped. Purchasing three yields a Fire Flower, while five or more results in a Star.
In ScareScraper mode, once players reach the top of the ScareScraper, a single firework will explode, followed by the words "You reached the top floor in ____ Mode!".
During the ending of Paper Mario, the procession of parade floats finally ends with Mario and Princess Peach. The float stops, and Mario and Peach get off the float to walk over to Mario's House. There, they view a display of fireworks as part of the ending screen. The fireworks display does not stop until the player reset the system.
In the Mario Baseball series, fireworks appeared at Mario Stadium during the night. It also appeared in the Bob-omb Derby minigame where players can create fireworks from the Bob-ombs using homeruns. In the final movie from Mario Super Sluggers, Mario and his friends get to watch the fireworks at Daisy Cruiser and Mario Stadium.
Fireworks frequently display in Mario Party 3. In the end of a Battle Royale or Duel, the winner of the game will be rewarded with fireworks the shape of the character's head. At the end of Story Mode, the Millennium Star will shoot regular fireworks for the character. Finally, at the beginning of the Staff Roll, fireworks the shape of the winning character's head will briefly be seen again.
In the ending cutscene, a single firework will be shot into the sky, and explode to create a constellation of the winning character.
 Mario Kart Wii
They appear in the Award Ceremony, coming in five colors: red, blue, green, pink, and yellow. They are first shown when the racers park by Peach's Castle.
In the Christmas-themed episode The Kongo Bongo Festival of Lights, the fireworks make an appearance twice. The first time is when the Kremlings see it during the day, and at the end of the episode in which the Kongs get to watch at the end of the festival.
In the GameCube game Donkey Kong Jungle Beat and its New Play Control! remake, the fireworks made an appearance twice. When Donkey Kong gets a Crest at the Sacred Tree, there will be fireworks in the background. More fireworks will explode if he collects more Crests. Another appearance of the fireworks is at the end of the game when Donkey Kong defeats Cactus King and Ghastly King.
In The Adventures of Super Mario Bros. 3, fireworks only appeared in the episode Crimes R Us. When King Koopa tried to open the two sacks, it turns out that the first one has the captured Koopalings, and that the second one contains a Bob-omb, which explodes, blowing up the Doomship and creating fireworks for Mario, Luigi and Clyde to see.