Wave of Exhaustion

Necro {b}(When you cast this spell, you may remove
a creature card with {b} in its casting cost from your
graveyard. If you do, this spell costs {b} less to cast.)
Creatures target player controls cannot attack you
this turn unless that player pays {1} for each
attacking creature. That player may not cast
spells or activate abilities that aren't mana
abilities this turn unless he or she pays an
additional {1} for each spell or activated ability.