My inventory gets full of crappy stuff while exploring so I feed the masks. Only takes a few seconds to unload a dozen items. Seems to help.

I don't feed him anything. The experience gained by equipment is really low. Just let it be it will level up on its own.

I think you have to feed it one orb just to turn it on... then don't bother feeding it any more, right?  Feed the skulls all the crappy equipment you pick up.

It's to feed ur skulls which u equip. 
Tip-its quiet useless cus it does not give that much exp(u can just farm and level those skulls up)+it's damn expensive so dont buy it is what I would recommend

Who's this guy for?? [FORGE]