DeathDealer

Bestow: {b}{b}{b}{b}
Enchanted creature has: "{t}: target player gains control
of DeathDealer. At the beginning of their next Attack
Phase, create X 1/1 black Tumor creature tokens, where
X is the number of creatures they own. Then, all of the
original creatures that player owns fight their respective
tumors. On their end step, that player gains X life,
where X is twice the number of creatures that died this
turn."
Flying