Big Scary Mouth

This spell costs {x} mana less to cast, and gets
+0/+X, where X is 6.
Frenzy 6
Afflict Y, where Y is 6 minus the total toughness
of creatures blocking Big Scary Mouth
At the end of each combat, destroy any number
of creatures blocking or blocked by Big Scary
Mouth with combined toughness less than or
equal to 6.