From the Super Mario Wiki
Retrieved from "http://www.mariowiki.com/index.php?title=Krockhead&oldid=2103203"
Krockheads, or KrocHeads, are crocodile enemies that first appeared in Donkey Kong Country 2: Diddy's Kong Quest and later Donkey Kong Land 2. Only the head of a Krockhead is ever seen. Despite being an enemy, they cannot harm the Kongs directly. Instead, their heads are helpful to them, the green variety acting as platforms and the brown as springboards. They can be found in either water or lava. In some levels, Krockheads bob up and down, making timing a necessity. Sometimes, they must be summoned to the surface using a Krockhead Barrel; however, this summoning is only temporary.
Although it's possible that these are a type of Kremling, their relationship to Kremlings is never confirmed.
Names in other languages