Mad Hatter, The Hypnotist

Deathtouch
When Mad Hatter, The Hypnotist enters the
battlefield, exile the top card of each opponent's
library. You may play cards exiled this way until
the end of your next turn and you may spend
mana as though it were mana of any color to cast
those spells.
"We're going to have company!"
—The Mad Hatter