Adamantine Golem

Indestructible, Trample
Adamantine Golem enters the battlefield with
twice X +1/+1 counters on it.
Unstable Antimagic - Whenever Adamantine
Golem becomes the target of a spell, roll a d20.
If the result is one, destroy all other creatures
you control. Otherwise Adamantine Golem gains
hexproof until end of turn and you place X
+1/+1 counters on Adamantine Golem, where X
is the result.