Trample (If this creature would assign enough damage to its blockers to destroy them, you may have it assign the rest of its damage to defending player or planeswalker.) When Crumbling Colossus attacks, sacrifice it at end of combat.
Official Rulings for Crumbling Colossus
9/22/2011 : If another player controls Crumbling Colossus when its ability tries to resolve, you'll be unable to sacrifice it. It will simply remain on the battlefield.
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