Utsuboankō (うつぼあんこう) is an enemy in the Game Boy Advance game Wario Land 4. They are only found underwater in the level Mystic Lake. Their appearance is based on the moray eel and the goosefish, known in Japanese as utsubo and ankō respectively. They are giant sea creatures, with their head alone being bigger than Wario. Only a part of their body is revealed, as they reside in holes in the walls. Utsuboankō are known to have a red and orange head, a green fin, bulging eyes, large lips, sharp fangs and yellow limbs that seem to resemble the feet of seabirds.
The sea creatures live in dark holes and will not crop up until Wario comes near. When they wait for prey in their holes, they can be recognized by their eyes glowing in the dark. The moment Wario comes nearby the hole, the Utsuboankō will quickly shoot out and bite for a short moment, revealing their sharp fangs. Afterwards, they will close their mouth and retreat again. They are only able to hurt Wario with a bite, otherwise they will simply block his path. Not every dark hole in the Mystic Lake is inhabited by an Utsuboankō, but the more challenging the game mode is, the more common they are. Wario is unable to defeat them.