That gold throwing demon...(question)

At the beginning of the new gameplay trailer there's a small demon with a big pot of gold. If you attack him, he runs around throwing the gold all over the place. A very cool idea btw :D

My question is: What happens if you don't kill him? I guess he won't throw endless amount of gold around? :P
Will he eventually run away? If that's the case, is it better to let him live (till he runs away) or to kill im instantly? (mabye he leaves more gold behind if you kill him faster!?)

Second question (and/or suggestion): Does he only throws gold? Or is there a slight chance that he's letting a gem or a rune behind!? (would be cool :P)

I hope there'll be a lot of monster types like this (with special mechanics) :)
...like a "bloodlust monster". If you kill it, its blood will make you attack 10% faster, so you wanna kill it first :P