Corpse-Chewer

Keen Smell. The Corpse-Chewer has advantage on Wisdom (Perception) checks that rely on smell.

Spider Climbb. The Corpse-Chewer can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Multiattack. The Corpse-Chewer makes two attacks: one with its tentacles and one with its bite

Tentacles Melee Weapon Attack: +4 to hit, reach 10 ft., one target. Hit: 4 (1d4+2) poison damage. The target must succeed on a DC 14 Constitution saving throw or be poisoned for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 7 (2d4+2) piercing damage