Ojawahn, Thunder Titan

Trample
Whenever you cast your fifth instant or sorcery
spell each turn, search your library for an instant
or sorcery card, cast it without paying it's mana
cost, then exile that card. Shuffle your library.
{w}{u}{b}{r}: Return target instant or sorcery card
from your graveyard to your hand. Activate this
ability only once per turn.