Champion of the Clachan (Lorwyn Eclipsed)

Creature — Kithkin Knight - Flash
As an additional cost to cast this spell, behold a Kithkin and exile it. (Exile a Kithkin you control or a Kithkin card from your hand.)
Other Kithkin you control get +1/+1.
When this creature leaves the battlefield, return the exiled card to its owner's hand.