Frelya, Glacial Overseer

+1: Until your next turn, activated and triggered abilities of target permanent can't be activated unless they're mana abilities.
-3: Create 1+X 0/3 blue Wall creature tokens with defender, where X is equal to the number of nontoken Walls you control.
-7: Tap all creatures an opponent controls. Those creatures don't untap during that opponent's upkeep.