Jellybean is a silly little character I bought from Angry_Koala from FA.
https://www.furaffinity.net/view/46050755/

Jellybean is a Venom-like symbiote. He likes latching onto people and changing their size and strength.
If he likes you, he will increaser your size even after he leaves, but if he doesn't like you, he will absorb your size and strength and add it to himself.
So, it pays to be nice to Jellybean if he comes around you.
Though, one side effect of having Jellybean on you is that for a while everything will taste like black licorice. :-P