Xataxji's Bauble

{5}, {t}: Draw a card. If it is an instant or
sorcery card, you may reveal it. If you do,
you may cast it without paying its mana cost until end of turn.
"That trinket ? Ah, yes. One of my favorites. It whispers, you see ? It whispers secrets. Whose, I
don't know. But it can always be useful."
— Xataxji