The Twins, Destructive Duo

As long as you have one or fewer cards in hand,
The Twins, Destructive Duo have vigilance and haste.

Whenever The Twins attack, look at the top six cards of your library. You may exile a legendary creature card from among them. Put the rest on
the bottom of your library in a random order.
Until end of turn, you may cast the exiled card without paying its mana cost.