Beast Within is a M Brute Action - Attack card from Flesh and Blood (Armory Deck - Rhinar, ARR).
M
Armory Deck - Rhinar (ARR)
Card Text
If Beast Within is put into a graveyard from anywhere other than the combat chain, banish the top card of your deck and lose 1{h}. If it has 6 or more {p}, put it into your hand, otherwise, repeat this process.