Academy Aegis

Enchant target Island or target nonenchantment,
nontoken Wizard permanent you control.
When Academy Aegis enters the battlefield,
choose a creature type. Whenever another player
casts 2 or more spells in a turn, that player taps
target permanent. It gains Sanctuary of the
chosen type and doesn't untap as normal during
its controller's next untap step. (Spells and effects
that target a spell or permanent of the chosen type cost
an additional {1} or 1 life.)