The Whisper

Your opponents play with their hands revealed.
Whenever The Whisper deals combat damage to
a player, exile a card from that players hand. For
as long as that card remains exiled, you may cast
it, and you may spend mana as though it were
mana of any type to cast it.
Whenever The Whisper deals combat damage to
a creature, exile it. Return it to its owners hand
at the beginning of the next end step.