Lockjaw

Lockjaw are a species of red piranha fish first appearing the water levels of Donkey Kong Country 2: Diddy's Kong Quest. They appear on Crocodile Isle and, in later appearances, Donkey Kong Island. Pink versions, called Snapjaws, are related to them.

Donkey Kong Country 2
Lockjaws here appeared in various aquatic levels. Unlike most water enemies, Lockjaws would actually attack the Kongs directly when in sight. If Diddy or Dixie get too close, Lockjaws will reel back, charging, and quickly rocket forward, aiming for the lead Kong. Lockjaws apparently get faster the later the level in the game.

Donkey Kong Land 2
Lockjaws return in Donkey Kong Country 2's follow-up, Donkey Kong Land 2. Their general attack sequence was not changed. Other than appearing as an enemy, they are featured on the cover for the book, swimming after Diddy Kong and Dixie Kong.

"DK" Series
Lockjaws reappeared in the Game Boy Advance game, DK: King of Swing and in the DS game, DK Jungle Climber. Here, they are rather weaker, capable of being defeated by simply being bashed into by Donkey Kong. Lockjaws attack by biting, as they have in their previous appearances.