Magic Barrier

Greater Spell {3}{w}(You may cast this spell for its
Greater Spell cost. If you do, it enters the battlefield
with a greater spell counter on it.)
Enchant creature.
Whenever enchanted creature would be dealt
damage by a noncreature source, prevent 1 of
that damage. If Magic Barrier has one or more
greater spell counters on it, prevent 2 of that
damage instead.