Loki, God of Mischief

When Loki, God of mischief enters the battlefield you may exile an instant or
sorcery from your hand and a creature
from your graveyard. Until end of turn,
you may cast cards exiled by Loki, God of Mischief without paying their mana
cost. Creatures cast this way gain Haste. At
end of turn exile all cards cast this way.