Gruesome Slaughter
Gruesome Slaughter BFZ
Battle for Zendikar Rare 
Cost: Mana 6
CMC: 6
Card Type: Sorcery
Oracle Text: Until end of turn, colorless creatures you control gain "Mana Tap: This creature deals damage equal to its power to target creature."
Flavor Text: Though Gideon arrived at Sea Gate too late to prevent the massacre, he still had enough time to lead its survivors to relative safety.