Clash is a mechanic from Lorwyn-Shadowmoor block in which you and an opponent reveal the top cards of your libraries and compare their mana values. The player revealing the card with the higher mana value wins the clash, after which the revealed cards can be left on top or moved to the bottom.
Typifying the effect, Marvo, Deep Operative rewards repeated clash victories, Release the Ants potentially returns itself to your hand after a win, and Lash Out deals additional damage when its controller wins the clash.
