It says: Cast and exhaust to lower a monster's toughness by 1 (to a minimum of 1) and ignore one of its special abilities other than Magical Immunity until the end of this combat.
Does word monster include "Ancient One"? If it does, can reduction of toughness be used (for example in 6-player game you'll need only 5 hits to take out doom token)? If so it's a great spell...
My hopes are crushed by the GOO!!!! I wish that I could at least remove GOO's special ability...
! I think there are 2 GOO-attack cancellers. But since you basically have just base Fight...
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