Cheep Chomp

Cheep-Chomps are Cheep-Cheeps that are bigger than usual and are first found in underwater levels in New Super Mario Bros.. They closely resemble a Boss Bass. These Cheep-Cheeps are purple with a green back-fin and have enormous mouths.

Super Mario series
In New Super Mario Bros., if Mario or Luigi swim too close to the Cheep-Chomp, it opens its mouth and try to eat the adventurer. The giant fish often follows the character around the screen while attempting to devour them. Success on their part causes the player to lose a life, regardless of the player's condition. They can be defeated, like all other fish, with a Fireball or being smashed by Mega Mario/Luigi. Only four appear in the entire game, all of them appearing in the same level: World 3-1.

In New Super Mario Bros. Wii, only two Cheep-Chomps appear: Once in a bonus area in 4-4, and again in a bonus area of 9-2. A Fireball or Starman takes the big fish down, but it is invincible to ice balls from Ice Mario. Two changes are made from New Super Mario Bros.: it is slightly bigger, and defeating it releases three 1-Up Mushrooms.

Cheep-Chomps once again appear in New Super Mario Bros. 2. One makes it first appearance early in World 1-5. When defeated, it releases 3 coins. They reappear as common enemies in World 4-5.

Paper Mario series
Cheep-Chomps shall reappear in the upcoming game Paper Mario: Sticker Star. In the trailer, one can be seen on the surface of the water in a jungle river, chasing Mario (who is riding a raft down the river). It jumps down when it reaches a waterfall. It appears to have mechanical features and a propeller-like tail.