It has to be a creature that died the turn this enters, but the reward for timing this right is a stack of treasure and a small bit of graveyard denial
The Strategy The strategy is to go elfballing to get Voja, Jaws of the Conclave as strong as possible while developing a card draw engine equivalent to the strength of your wolf army
The cards you can turn into creatures have to cost more than four mana, and Bello costs three, so you need Bello to stick around for a bit and you have to have several enchantments in play to really keep the pressure up
Restraining it to effects like other creatures you control gain hexproof and you have hexproof is a much better way to use the ability
And then the rest of the deck is UB Spellslinger stuff, weve got classic draw support from Archmage Emeritus or a Stinging Study, tutors with Dark Petition, removal and draw with Decree of Pain, and so on