Harovengi Deathrider

Haste, undying (When this creature dies, if it had no +1/+1 counters on it, return it to the battlefield with a +1/+1 counter on it.)
When Harovengi Deathrider enters the battlefield from your graveyard, create a 4/4 black Demon creature token with flying, you lose
4 life, and sacrifice Harovengi Deathrider.
He made a pact for immortality in life, but he didn't bother to read the fine print.