Pompous Battlemage // Improvised Act

A creature with a prepare spell can't become prepared more than once at the same time. For example, say Bloodline Recollector is on the battlefield and is prepared. During the current turn, three creatures die. At the beginning of the end step, Bloodline Recollector's last ability triggers. When that ability resolves, since Bloodline Recollector is already prepared, the ability won't cause it to become prepared a second time or create a second copy of Ancestral Craving in exile.

If an effect causes a creature to become unprepared, a prepared creature stops being prepared and the associated copy of its prepare spell in exile ceases to exist. If it wasn't prepared at that time, nothing happens.

A preparation card is a creature card in every zone. For example, while it's in your graveyard, Diviner of Victory is a blue creature card whose mana value is 1. It can't be the target of Stingcaster Mage's triggered ability ("When this creature enters, target instant or sorcery card in your graveyard gains flashback until end of turn. The flashback cost is equal to its mana cost.").