Korhe, Cursed Immortal

This card must attack if able.
If this card would die, regenerate it and put a
+1/+1 counter on it. If this card has 3 or fewer
+1/+1 counters on it, this ability activates only
once per turn.
If this card has 4 or more +1/+1 counters on it,
it gains first strike.
If this card has 5 or more +1/+1 counter on it,
it gains trample.