Oisin, Gore Incarnate

Trample
Whenever a creature dies gain an experience counter.
Oisin, Gore Incarnate get +1/+1 for half the amount of
experience counters you have, rounded up.
If Oisin, Gore Incarnate would die or be put into exile
instead lose half of the amount of experience counters
you have, rounded up then transform Oisin, Gore Incarnate.