A Mega Mushroom (メガキノコ) is a super-sized mushroom that Mario or Luigi can eat to grow super-sized themselves. First appearing in Mario Party 4, it grants the user destructive strength over anything in their path for a limited amount of time.
In the Mario Kart series, the Mega Mushroom Item has been in a limited number of games, including Mario Kart Wii and two Mario Kart Arcade games, Mario Kart Arcade GP and Mario Kart Arcade GP DX (called the Giant Mushroom [巨大キノコ] in the latter two). In all games, the super-huge shroom grows the player to an immense size to gain speed and squash opponents.
After eating a Mega Mushroom, your character will enlarge by two or three times (and the catchy Super Mushroom music will play from New Super Mario Bros.). At this size, most small arms Items (such as Red Shells or Bob-ombs) or course obstacles (like the vehicles on Moonview Highway or Moo Moos on Moo Moo Meadows) will have no affect on you. In fact, even if Lightning or a Thunder Cloud strikes, your racer will only shrink down to normal size! Bullet Bills, Starmans, and falling off the edge are the only weaknesses of the Mega Mushroom.
Probably the best attribute of the Mega Mushroom is the ability to flatten any racers that you catch up to. Instead of just knocking them over with a Star, the Giant Shroom will drive right over enemy racers, crushing them down like a Thwomp or a dinosaur from Dino Dino Jungle. Although the effect isn't as long as Thwomps or the dinosaur, it still tremendously stops their acceleration and caps their top speed for a while.
If no enemy Items or opponents are in sight, the Giant Mushroom still comes in handy because it grants a passive amount of speed (about equal to a Star), and off-road sections of the course can be traversed without slowing down. Just be careful when taking shortcuts, as it can be difficult to know when the huge-effect will wear off... you could find yourself stuck in the middle of nowhere.
There's a few options to defend against being smushed by a Mega Mushroom. One is to be either armed with a Star or a Bullet Bill, and since those are usually not available in the upper places (the ones most likely to be victims), your best bet is to either steer well clear of them or hope your vehicle is fast enough to out-last them. However, it you hear the warning alarm, it's usually too late... just enjoy your last moments before being squished...
- It's recommended to use a kart when trying to smash other racers, as a bike just doesn't have as much surface area.
- One of the reasons why the Mega Mushroom only appears in Mario Kart Wii is because people find it to be a lot less powerful than the Starman, and they'd rather have that than this.
- If two racers have used a Mega Mushroom, but one also uses a Star, then the racer without a Star will also get squished.
- The Mega Mushroom was originally going to reappear in Mario Kart 7, but it was scrapped due to incomplete functions. Its codes are still in the game's data.
- Mario Kart Arcade GP DX's version of the Giant Mushroom has a slightly tanner head.
- In Mario Party 4, the Mega Mushroom originally had a green cap (similar to the 1-Up Mushroom), but in New Super Mario Bros., it gained its common yellow and red appearance (likely modeled after the original Super Mushroom from Super Mario Bros.)