Gluto
From Wikitrix
Pilot of the Resolution, Tetrax's ship, Gluto is a gelatinous, slime-based lifeform who debuts in Ben 10: Secrets of the Omnitrix. Gluto can shapeshift to a degree, which comes in handy when piloting a ship that requires at least three arms to run properly. Gluto wears a suit that allows him to walk on legs for better mobility. His only naturally distinct features are his three eyes and two antennae-like tentacles.
Gluto quickly develops a fondness for Gwen, who sneaked onto the Resolution, which provokes him to place himself in harm's way to help her. When Vilgax's forces invade the ship, Gluto attacks Vilgax himself, and Gluto is seemingly killed when one of Vilgax's drones explodes after he has enveloped it. Later, it is revealed that Gluto has regenerative capabilities, as he saves Gwen from vicious Floraunas before joining in during the final battle. After Vilgax is defeated, Gluto is revealed to be able to speak English, of which Ben had been unaware; Tetrax, when questioned about Gluto's regeneration and speech ability, replies humorously, "Who knew?"