Pact of the Bloodmage

Enchant creature you control
Enchanted creature gets +3/+3 and has foul.
(At the beginning of your upkeep, put a -1/-1
counter on this creature. Whenever this creature is
blocked by a creature, move a -1/-1 counter from
this creature onto that creature.)
Whenever the enchanted creature dies,
distribute all -1/-1 counters on it as you choose
among creatures your opponents control.