Mohmoo is a massive sea cow from the Grand Line who arrived with Arlong's crew. The creature infamously destroyed Gosa Village during their takeover, though it seems perfectly capable of moving on land despite its aquatic nature.
Things went south fast when Mohmoo ran into Luffy, Sanji, and Yosaku. The trio made quick work of the beast, then basically just. repurposed it as a tow animal for their boat. Not exactly the dignified role Mohmoo was used to.
During the final battle at Arlong Park, Hatchan—the sea cow's actual caretaker—called Mohmoo into the fight to help turn the tide. The creature remembered its first loss to Luffy and probably should've sat that one out. Instead, it ended up as the unfortunate target of Luffy's Gomu Gomu no Kazaguruma, a spinning attack that decimated most of Arlong's forces in one shot. Mohmoo got thrown clear out of the park and vanished from the story entirely after that.
The creature can moo like a regular cow, which is darkly funny given what it is. Fans have speculated it might be an ophitauros based on its appearance.
First Appearance: Chapter 73; Episode 31
Content compiled by AnimeList.moe from publicly available sources.
