Nep-Enut

Just made it!

Nep-Enut is a huge, blue monster that hides underwater in the game Super Mario World 2: Yoshi's Island. Nep-Enut will remain submerged until Yoshi approaches him. Then, the monster will rise, blocking Yoshi’s path. If Nep-Enut’s mouth is hit with an egg, he will return to the water to hide (and only his eyebrows will remain visible). If Yoshi jumps over the giant monster, Nep-Enut will give chase. In Yoshi's Story Nep-Enuts are only found in the Piranha Grove.

Other notes

The Super Mario World 2: Yoshi's Island box art and game cover shows Yoshi about to cross a gap with a Nep-Enut in hot pursuit.

Nep-Enuts have their own level named after them in World 3, Nep-Enuts Domian.

Switch the last four letters in Nep-Enut, and you get "Neptune", the God of the sea.

The Nep-Enut is to water as the Gargantua Blargg is to lava.