Derevi, Empyrial Tactician [Commander 2013] Angel destroy Cosmic Horror unless you

destroy Cosmic Horror unless you pay {3}{B}{B}{B}

Whenever Derevi

Set: Unlimited Edition Type: Artifact Rarity: Rare Cost: {3} {1}: The next time an unblocked creature of your choice would deal combat damage to you this turn

which can be quite unsettling for their prey

Battle doesn't need a purpose

Derevi, Empyrial Tactician [Commander 2013] Angel destroy Cosmic Horror unless youSet: Commander 2013 Type: Legendary Creature Bird Wizard Rarity: Mythic Cost: {G}{W}{U} Flying Whenever Derevi, Empyrial Tactician enters the battlefield or a creature you control deals combat damage to a player, you may tap or untap target permanent. {1}{G}{W}{U}: Put Derevi onto the battlefield from the command zone.