The Aku Aku/Uka Uka Masks are weapons used in CTR and CNK. They make the player temporarily invincible. As the player's kart goes, it travels faster and faster in the duration of the mask's use and also, wumpa won't be lost if the player falls into an abyss. While using them, the player can crash into opponents and make them spin out. While using it, the race track's music is interrupted by different music. The music that plays depends on which mask the player is using. Juiced up masks last a bit longer and the wielder moves even faster.