Oracle

Plane - Zendikar 

Creatures with power 7 or greater can't attack or block.
Whenever you roll Chaos, create a 7/7 colorless Eldrazi creature token with annihilator 1. (Whenever it attacks, defending player sacrifices a permanent.)

Officiele rulings

6/1/2012
A creature’s power is checked when attackers or blockers are declared. Increasing the power of an attacking or blocking creature to 7 or greater won’t remove that creature from combat.

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