Siofra, Covenant Crafter

Flying
Whenever a creature card is exiled, you may pay {b}. If you do, that card is instead exiled with a Fae-Taken counter on it.
{x}{u}: Exile Siofra, Covenant Crafter. Return it to the battlefield at the beginning of the next main phase, except it enters as a copy of a creature with a Fae-Taken counter on it with mana value {x} or less and it has flying and this ability. This ability costs {1} less to activate for each card in exile with a Fae-Taken counter.