Bloopers (also known as Bloobers) are squid-like creatures that are found in the ocean. They made their first appearance in Super Mario Bros., and various kinds of them have appeared in most Mario games since, normally as enemies. Mario Party 8 was the first game to feature a Blooper as a playable character. Bloopers come in different sizes and colors, though the original variety shown in Super Mario Bros. is white and roughly the size of a Koopa Troopa. They possess varying numbers of tentacles (ranging from four to up to ten visible limbs) of various lengths, which help them move and are in some of their appearances used directly to attack the player. As shown in some games, like the Mario Kart series, Bloopers can survive in and out of the water.

Bloopers are also used as an item in Mario Kart DS, Mario Kart Wii, and will also be in the upcoming Mario Kart 7. After the player has launched it, the Blooper will create a large ink blot on the screen of all the drivers who are currently in a higher rank than the player, which obstructs the driving view of opponents and causes CPU characters to swerve around on the track. The higher rank a player is, the more ink that gets splattered on them. If used while in first place, it can backfire and cause ink to block the driver's screen. To get rid of the ink, the player can use a Mushroom, go on a Boost Pad, or wait for it to go away. Also, in Mario Kart Wii, there is a medium-sized kart called the Turbo Blooper that is based on a Blooper.

The Blooper will make its third appearance as an item in Mario Kart 7.