A idea I had involving a fusion/merge co-op with Lupa and Vivi thus making Glutton Mode.

Glutton Mode increases Lupa's appetite dramatically causing her to eat pretty much anything that's in sight, but she has some control but not a lot, due to Vivi's Void and Frenzy Genetics activating when fused with Lupa.

While in Glutton mode, Lupa's body is a lot more durable, with stretchy arms, and body (not Elastic though) to reach hard to reach places, and contain/consume a LOT, along with the consuming, while in glutton mode, Lupa can consume even uneatable objects, like robots, machinery, and many other things, and they digest like normal food making normal fat like if she ate stuff while normal.

after Glutton mode is done Vivi flys out of Lupa but Lupa gets very stuffed and sometimes too full to move, so they go back home or in a safe place while she tries to digest, and Vivi relaxes on Lupa's belly in turn.

These two are sure a Gluttonous Duo XD

Hope ya like it

Lupa (Glutton Mode) -> me