Banderhobb from Volo's Guide to Monsters
Swallow. The banderhobb makes a bite attack against a Medium or smaller creature it is grappling. If the attack hits, the target is swallowed, and the grapple ends. The swallowed creature is blinded and restrained, it has total cover against attacks and other effects outside the banderhobb and it takes 10 (3d6) necrotic damage at the start of each of the banderhobb’s turns. A creature reduced to 0 hit points in this way stops taking necrotic damage and becomes stable.