Schmedward, The Siren

Cast this spell only during an opponent's turn,
before attackers are declared.
Creatures the active player controls attack this
turn if able.
At the beginning of the next end step, destroy all
non-Wall creatures that player controls that didn't
attack this turn. Ignore this effect for each
creature the player didn't control continuously
since the beginning of the turn.
He meowed and meowed and meowed and meowed and meowed and meowed and meowed and meowed and meowed and meowed and meowed and