From the Super Mario Wiki
A Super Mushroom is a red Mushroom that serves a particular function depending on the game in which it is found. Its first and most common effect is causing Mario or Luigi to double in size and strength, allowing them to smash through bricks and take an extra hit from enemies. An opposite can be considered as the Poison Mushroom, a Mushroom that hurts the player. Both this and the standard Mushroom are designed after the Amanita Muscaria mushroom, which is ironically poisonous.
The idea for Super Mushrooms were originally believed to have been inspired by the cake that Alice eats in Alice's Adventures in Wonderland that makes her grow after having been shrunk by a potion. However, Shigeru Miyamoto later corrected himself, saying that this was a misunderstanding; the mushrooms were actually inspired by the concept of mushrooms being associated with magical worlds in general, like the Wonderland of Alice's Adventures in Wonderland and the Mushroom Kingdom.
Super Mario series
Super Mario Bros.
Super Mario Bros. is the first Mario game to feature Super Mushrooms. They are the most common items found in the game and touching them will make Mario grow into Super Mario. When Mario is Super Mario, he can take one more hit from an enemy and revert back to normal Mario before losing a life, and gains the ability to break brick blocks. When Mario already has a Super Mushroom, usually a Fire Flower appears instead. Also, when Mario shrinks, he will be invisible and invincible temporarily. The pattern on the top resembles the pattern on a Mega Mushroom. Players can make Super Mushrooms change direction by hitting the blocks they move along.
1-Up Mushrooms also appear. They are quite rare and sometimes tough to obtain; some are in life-threatening situations while others are found in hidden blocks that are invisible until Mario hits them.
Super Mario Bros.: The Lost Levels
Super Mario Bros.: The Lost Levels is very similar to Super Mario Bros. in terms of gameplay and items, and the Mushroom returns. Also, Super Mushrooms receive eyes in this game for the first time, unlike the Super Mushrooms in Super Mario Bros., and Super Mario Bros. 2, making them look even more like Mega Mushrooms. Super Mushrooms look almost identical to the Poison Mushroom, except they are slightly darker in color.
Super Mario Bros. 3
In Super Mario Bros. 3, Super Mushrooms and 1-Up Mushrooms again return, but still grant the player the same ability. The only changes that were made was the sprite appearance. In the original Super Mario Bros. 3, Super Mushrooms are colored white with red spots. In the Super Mario All-Stars remake, those colors are flipped; red body and white spots. The Poison Mushroom makes no appearance in this game.
Super Mario World
Mushrooms and 1-Up Mushrooms reappear in Super Mario World and no changes had been made to them. However, Mushrooms tend to "leap" out of the bushes sometimes for the player to receive. Fishin' Lakitus also use 1-Up Mushrooms as bait for Mario and after Mario had collected it, the Lakitu will attack. 1-Up Mushrooms will also appear instead of Yoshis from the eggs if Yoshi is already ridden on.
Super Mario 64 DS
Super Mushrooms (called just Mushrooms in the manual) appear in Super Mario 64 DS, but this time, they make the characters grow extremely large for a limited time, similar to the effect of a Mega Mushroom. This allows the characters to destroy objects or enemies simply by touching them. They earn an extra life for each object or enemy that they destroy after the first seven.
New Super Mario Bros.
In New Super Mario Bros., Mushrooms and 1-Up Mushrooms return, along the addition of 2 new mushrooms: the Mini Mushroom and the Mega Mushroom. The Mini Mushroom will make the player grow to a very small size. In this condition, the player may walk on top of water and have floating jumps. The downside is that Mario will lose a life if he touches an enemy and he can only defeat them by ground-pounding them. Mega Mushrooms have an opposite effect. It will make Mario grow to a tremendous size, which will allow him to smash through most objects and become invincible. The downside is that Mega Mario cannot destroy all blocks and he may get stuck. Depending on the amount Mario destroyed, Mario will receive 1-Up Mushrooms.
Mushrooms can act like platforms. There are some types of bouncy mushrooms that will make Mario bounce on them. Others grow and shrink, become taller and shorter, and tilt down according to where Mario is.
New Super Mario Bros. Wii
In New Super Mario Bros. Wii, the Mushrooms got little or no change except the amount of Mushrooms that appear out of blocks depends on the amount of players there are. Also when a character obtains a Super Mushroom (or any power-up) the character will sparkle and glow for a few seconds. A new Mushroom called the Propeller Mushroom appears, granting Mario the ability to become Propeller Mario that will enable him to fly through the air.
Super Mario 3D Land
Super Mario 3D Land is the second 3D game, but first original 3D game to have Super Mushrooms included. They cure Small Mario, in the same way as in the side-scrollers. If Mario collects a Super Mushroom when the player already has an item stored, the player earns ten coins instead. Poison Mushrooms also return. They also are not as necessary since Mario starts out as Super Mario if he is to lose a life. Morty Moles also drop a Super Mushroom sometimes.
New Super Mario Bros. 2
Super Mushrooms appear in New Super Mario Bros. 2, acting the same as they did in previous side-scolling games. The Mega Mushrooms and Mini Mushrooms also return in this game.
New Super Mario Bros. U
The Super Mushrooms appear in New Super Mario Bros. U, acting the same as in other games.
Super Mario 3D World
Super Mushrooms return in Super Mario 3D World acting the same as in other games. However, like in Super Mario 3D Land, they aren't necessary, because Mario/Luigi starts off as Super Mario/Luigi. Princess Peach, Toad, Captain Toad and Rosalina can also grab Super Mushrooms.
The Goomba Towers somtimes carry Super Mushrooms and the player can touch the screen to pop the bubble to get them from the Goomba Towers.
Captain Toad: Treasure Tracker
Super Mushrooms also returns in Captain Toad: Treasure Tracker which acts the same in Super Mario 3D Land.
Donkey Kong (Game Boy)
Super Mushrooms also make an appearance in Donkey Kong for the Game Boy. They are used by Donkey Kong during the final battle. He ends up using several of them to transform himself into a giant. A Super Mushroom is also briefly seen in the ending when Pauline gives one to Mario, so that he can change his size and catch Donkey Kong when he is falling.
Mario & Wario
In Mario & Wario, if a blind character gets a Mushroom on the floor, the item magically gives the player more time to complete the level the player is on. Unfortunately, it only appears in certain levels that need more time.
The Super Mushroom appears in Hotel Mario. It doesn't make Mario big or small, but gives him the chance to take one hit and not lose a life. The only difference between the normal Mario and the one that ate the Super Mushroom is the color of his overalls.
Mario Party 7
In the Pearl Hunt sub-game from Mario Party 7, one of the obtainable items is a Super Mushroom, although it's golden. The real Super Mushroom is just called "Mushroom". Due to how Pearl Hunt works, the Super Mushroom gives the player two extra tries.
Super Smash Bros. series
In Super Smash Bros. Melee, the Super Mushroom allows the player to grow to an incredible size, thus making them heavier and harder to knock off.
In Super Smash Bros. Brawl, the Super Mushroom has an additional effect. Not only are the fighter's size and weight increased, but their attack strength also increases. An attack that normally does 15% damage could do near 30% damage when the fighter is a giant. Specifically, those attacks deal nearly twice the normal damage.
Super Smash Bros. Melee
Super Smash Bros. Brawl
Super Smash Bros. for Nintendo 3DS / Wii U
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