Bopapodamus

Bopapodamuses are hippopotamus-like creatures that appear in Donkey Kong Country Returns and Donkey Kong Country Returns 3D. They only appear in the Forest world where they appear in several levels.

The Bopapodamuses are minor obstacles that the Kongs must jump on in order to get through gaps the Kongs cannot jump across; however, they can only jump on the Bopapodamus four times, after that it falls into the abyss, likely taking out the Kongs with it. If the Kongs do not make direct contact with the Bopapodamus's head, it will simply swat them away, causing them to fall and lose a life.

Trivia

 * Bopapodamuses where originally were supposed to appear in Donkey Kong Country: Tropical Freeze, but never made it in the final game. According to concept art they were supposed to float on water surfaces instead of being on poles.

Reference
Pogopotamus