Ymir the Founding Titan

Indestructible
{b/g}{b/r}: Ymir the Founding Titan gains one of the
following until end of turn. Double Strike,
Trample, Lifelink, Hexproof, or Menace. Put
a +1/+1 counter on Ymir the Founding Titan.
At the beginning of your end step place put a
+1/+1 counter on Ymir the Founding Titan.
Then if its power is 13 or higher, sacrifice it.