Niata

Niata is an Alien creature from planet ZUKKARON, who escaped to earth while it was being raided. Rick disguises her as his cat but she actually eats the evidence of his crimes and can in fact speak. Almost no one knows about this. They made a deal where he has to feed her candy (in order for her not to die) in exchange for being his accomplice. Before meeting Rick they have never been in the need to use their abilities. It's all about survival for her.

She can open her mouth up to a meter and regenerate parts of her body at will. She does not know what a tummy ache is. Her insides work just like hydrofluoric acid and nothing she eats or drinks will hurt them. Rick does find her personality and severe hyperactivism a bother. Still, they both need eachother to fulfill their needs.

Aditional info:
She/it/they
Ageless
Infertile, no genitals. Was created, not born
No concept of time
Silly. Causes destruction anywhere it goes
Is smiling like 90% of the time unless scared/starving/confused