Alastor, the Radio Demon

Shroud, Shadow

Let's make a deal — At the beginning of each opponent's upkeep, if they control no creatures with a deal counter on them, place a deal counter on target creature they control.

When a creature with a deal counter on it would leave the battlefield exile it instead. Then your opponent chooses, either you make treasure tokens equal to it's mana cost, or you return it to the battlefield under your control.