Poisonous Dust

Enchant Creature. This card costs Y mana less to
cast, where Y is the number of creatures your
opponent controls. When this card enters the
battlefield, copy it X times, targeting new cards.
Enchanted creature gets -1/-1. During enchanted
creature's controller's end step, put a copy of this
card on to the enchanted creature. When
enchanted creature dies, move this card to another
creature. If there are no targets left, then put this
card onto the player that controlled it, except, with