Thrall the Earth-Warder

Attacking creatures you control have double strike.
{x}{g}{u}{r}, {t}, Sacrifice another creature: Reveal cards from the top of your library until you reveal a creature card. Put that card onto the battlefield and the rest on the bottom of your library in a random order. Put X +1/+1 counters on that creature. It gains haste.
"For Doomhammer!"