Red Shell

Red Shells are a type of shell worn by Koopa Troopas and Koopa Paratroopas throughout the Mario franchise. They first appear in Super Mario Bros., and are a recurring item within the Mario Kart series, in which they home in on the nearest opponent, causing them to spin out upon hitting them. The first Sega game that Red Shells appear in is Mario & Sonic at the Olympic Games for the Wii. Red Shells appear throughout the Mario & Sonic series, especially in Dream Events, where they act the same as in the Mario Kart series.

Mario & Sonic at the Olympic Games (Wii)
In Mario & Sonic at the Olympic Games for the Wii, Red Shells are a homing item featured in two Dream Events: Dream Race and Dream Platform. In Dream Race, a Red Shell functions like in the Mario Kart series in that it can be thrown forward and home in on the nearest opponent who, upon being hit, briefly loses speed. A character can avoid a Red Shell by using a Starman, invincibility from a Chaos Emerald, or by jumping over it. In Dream Platform, a Red Shell can break any Brick Blocks while homing in on their target, but can be blocked by using a Barrier.

Mario & Sonic at the Olympic Games (Nintendo DS)
In Mario & Sonic at the Olympic Games for the Nintendo DS, Red Shells appear in three Dream Events: Dream Race, Dream Long Jump, and Dream Canoe, acting as a homing item in all three of them. In Dream Race, Red Shells act similarly as in the Wii version of the Dream Event, and can be blocked by using a Shield. In Dream Long Jump, if a character is hit by a Red Shell, they lose height, although they can block it by using either a Shield or a Starman. In Dream Canoe, if a character is hit by a Red Shell, they lose three coins to whoever threw the Red Shell.

Mario & Sonic at the Olympic Winter Games (Wii)
In the Wii version of Mario & Sonic at the Olympic Winter Games, Red Shells are featured as homing items in numerous Dream Events, including Dream Alpine, Dream Ski Cross, Dream Snowboard Cross, Dream Short Track, and Dream Bobsleigh. In any of these missions, if a character is hit by a Red Shell, they are briefly slowed, but can use a Shield or a Super Star to protect themselves against it, like in Mario & Sonic at the Olympic Games.

Red Shells are also an item in the Individual version of Dream Ski Jumping, where they home in on an opponent. If a character is hit, they lose height, speed, ten points and a Bonus panel, although they can use a Barrier to protect themselves from a Red Shell.

Red Shells also appear as items in Dream Curling, where they turn the curling stone into a Red Shell that homes in on the pins when thrown until it comes to a standstill.

In the Individual and Team versions of Dream Gliding, a Red Shell homes in on the nearest opponent, whom it knocks out of the sky upon hitting them.

Mario & Sonic at the Olympic Winter Games (Nintendo DS)
In the Nintendo DS version of Mario & Sonic at the Olympic Winter Games, Red Shells appear as items in Ski Cross Racing, Rocket Ski Jumping and Extreme Snowboarding, where they can be thrown forwards or backwards, and home in on whoever is closest to the use in that direction. In all three Dream Events, a Red Shell can be blocked by using either a Shield or a Super Star, like in the Wii version of Mario & Sonic at the Olympic Winter Games.

Being hit by a Red Shell has varying effects depending on the event; in Ski Cross Racing, being hit causes the character to lose speed and Rings; in Rocket Ski Jumping they lose speed, height and energy, similar to Dream Long Jump from Mario & Sonic at the Olympic Games's Nintendo DS version; and in Extreme Snowboarding, the character is only briefly knocked over when hit.

Mario & Sonic at the London 2012 Olympic Games
In the Wii version of Mario & Sonic at the London 2012 Olympic Games, Red Shells are an item in several London Party minigames.

In the Nintendo 3DS version of Mario & Sonic at the London 2012 Olympic Games, the Red Shell and Green Shell appear on a badge that can be obtained from the badge machine.

Mario & Sonic at the Sochi 2014 Olympic Winter Games
Red Shells appear in Snow Day Street Hockey in Mario & Sonic at the Sochi 2014 Olympic Winter Games, where Piantas occasionally swap the puck for one if it is shot into their box. Red Shells move faster and bounce further than the standard puck, but not as much as the Green Shells.

Mario & Sonic at the Rio 2016 Olympic Games (Wii U)
Duel Beach Volleyball in the Wii U version of Mario & Sonic at the Rio 2016 Olympic Games features Red Shells as a homing item. Hitting an opponent with a Red Shell adds 10 Duel Points to its user's supply. A player can also hit the parade float with a Red Shell, which causes the Octuses to shoot energy balls at the opposing team and also award the player Duel Points.

Mario & Sonic at the Olympic Games Tokyo 2020
In Mario & Sonic at the Olympic Games Tokyo 2020, Red Shells are items in Dream Racing, in which they retain their basic functionality from the Mario Kart series. A Red Shell homes in on the racer in front of the user and hits them, causing them to briefly spin out of control and drop several of their Rings. A Red Shell hovers slightly above the ground while it is in use, unlike the Mario Kart series.

Super Smash Bros. series
In the Super Smash Bros. series, Red Shells are an object featured in Adventure Mode: The Subspace Emissary in Super Smash Bros. Brawl and in Smash Run in Super Smash Bros. for Nintendo 3DS, both in which they act very similarly as in the Super Mario series. In both games, Koopa Troopas and Koopa Paratroopas with a Red Shell behave differently from those who wear a Green Shell, although the shells act the same as one another. If a Koopa Troopa is hit, regardless of its shell color, it retreats into its shell, whereas hitting a Paratroopa turns it into a Koopa Troopa. Like Green Shells, if a Red Shell is thrown, it continues in a single direction until bumping into an object or by falling into a pit, like in the Super Mario series. After a while, the Koopa Troopa reemerges from its shell.

In Super Smash Bros. Brawl, a group of three Red Shells, known as Triple Red Shells, are featured as a sticker, which depicts their Mario Kart: Double Dash!! artwork. Applying a Triple Red Shells sticker to a fighter increases their launch resistance by 21.

In Super Smash Bros. for Wii U, Mii Fighters have their own headgear of a Red Shell, known as a Red Shell Hat.

The Red Shell serves as the basis for the Red Shell Hat headgear for the Mii Fighters in Super Smash Bros. for Wii U.

The first appearance of Red Shells in the Super Smash Bros. series was actually Super Smash Bros. and then in Super Smash Bros. Melee, although neither game has representation for Sega-owned franchises. Super Smash Bros. Melee has an Adventure mode that features Red Shells as objects worn by Koopa Troopas and Koopa Paratroopas, and the Red Shells in Adventure mode function the same as they later would in Super Smash Bros. Brawls Adventure Mode: The Subspace Emissary and Super Smash Bros. for Nintendo 3DSs Smash Run. As an item, a Red Shell retains its homing capabilities from the Mario Kart series, although a Red Shell can target any fighter, including the user, before it disappears after a while.