Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.
{2}{U}
Imprisoned in the Moon
Enchantment - Aura
Enchant creature, land, or planeswalker
Enchanted permanent is a colorless land with "{T}: Add {C}" and loses all other card types and abilities.
{W}{U}{B}
Void Rend
Instant
This spell can't be countered.
Destroy target nonland permanent.
{1}{W}{U}{B}
Zur the Enchanter
Legendary Creature - Human Wizard
Flying
Whenever Zur the Enchanter attacks, you may search your library for an enchantment card with mana value 3 or less, put it onto the battlefield, then shuffle.