House Lannister. Loyal.
Event. Cost: 1.

Action: Put a character into play from your hand. At the end of the phase, if that card is still in play, discard it from play (cannot be saved).

Cris Griffin
Core Set #100.

Link: Decklists

Hear Me Roar!

At first this card seemed meh, but now that The Hound is out, this card looks better. Put out your Hound for 1G (for free if fealty) when opponent is not expecting, win challenge, and just take Hound back.

Rules FAQ

“At the end of the phase” effects are delayed effects that initiate (and resolve) in an order decided by the first player - regardless of the order the effects that created them were played. In the case of Hear Me Roar and Tears of Lys, the FP would decide whether that Unique Lannister wound up in the dead pile, or the discard pile. ​After this, reactions to the phase ending (or to that poor, poisoned character dying) proceed in the usual order.

In order to play Hear Me Roar, you check play restrictions, pay costs and choose the target (revealing it) before your opponent decides whether or not to cancel the initiation. This is detailed on page 10 of the RRG under "Initiating Abilities".