Zetsu! If he has jail mates he can just eat them xd
If he runs out, well, there's always photosynthesis. He is a plant after all. But I think sunlight is required o_o d'ah well. xd
Raikage for sure he wont have any cell mates or any cell block mates and the guard would send remote control cars to communicate with him.He has the hulks body mass.
Second would be Orochimaru he would be a creep that shanked somebody everday and raped and ate their dead bodies.He would have to be put in solitary confinement.