Nekusar Knowledge Keeper

Split second(As long as this spell is on the stack, players can't cast other spells or activate abilities that aren't Mana abilities.)
When Nekusar Knowledge Keeper enter's
the battlefield, Copy {x} Instant's and
sorcery's played this turn.
{t}{p/u}{p/b}{p/r}: Return target Instant or Sorcery
to your hand.