msem-instigator

Improve {R/W} ({R/W}: Put a +1/+1 counter on this creature. This costs {1} more to activate for each +1/+1 counter on it. Improve only as a sorcery.)
Whenever an embattled creature you control attacks, you may exile the top card of your library. During any turn you attacked with an embattled creature, you may play that card. (A creature is embattled if it has a counter on it or has a permanent you control attached to it.)