Demiurge, Nazarick Tactician

Whenever a creature your opponent controls dies
put a soul counter on Demiurge.
Demiurge has +1/+1 for each soul counter on it.
Remove 4 soul counters from Demiurge: Gain
control of target creature an opponent controls
until end of turn. Untap that creature. It gains
haste, sacrifice that creature at the beginning of
the next end step.