Camouflage

Cast Camouflage only during your declare attackers step.

This turn, instead of declaring blockers, each defending player chooses any number of creatures he/she controls and divides them into a number of piles equal to the number of attacking creatures for whom that player is the defending player. Creatures he/she controls that can block additional creatures may likewise be put into additional piles. Assign each pile to a different one of those attacking creatures at random. Each creature in a pile that can block the creature that pile is assigned to does so. (Piles can be empty.)