Imp Pyre

When Imp Pyre enters the battlefield, remove all counters on the battlefield and add that many -1/-1 counters to it.
If one or more counters would be put on a permanent or player, instead put that many -1/-1 on Imp Pyre.
Whenever Imp Pyre gains one or more counters, deal damage equal to the number of -1/-1 counters on Imp Pyre.