Action Oriented Eye Monger

Antimagic Gullet. Magical effects, including those produced by spells and magic items but excluding those created by artifacts or deities, are suppressed inside the eye monger’s gullet. Any spell slot or charge expended by a creature in the gullet to cast a spell or activate a property of a magic item is wasted. While an effect is suppressed, it doesn’t function, but the time it spends suppressed counts against its duration. No spell or magical effect that originates outside the eye monger’s gullet, except one created by an artifact or a deity, can affect a creature or an object inside the gullet.

False Appearance. If the eye monger is motionless and has its eye and mouth closed at the start of combat, it has advantage on its initiative roll. Moreover, if a creature hasn’t observed the eye monger move or act, that creature must succeed on a DC 18 Intelligence (Investigation) check to discern that the eye monger is animate.

Unusual Nature. The eye monger doesn’t require air.

Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 12 (2d6 + 5) piercing damage, and if the target is a Medium or smaller creature, it must succeed on a DC 18 Dexterity saving throw or be swallowed by the eye monger and deposited in the eye monger’s gullet (see Antimagic Gullet). The eye monger can swallow one creature at a time. A swallowed creature is blinded and restrained, has total cover against attacks and other effects originating outside the eye monger, and takes 35 (10d6) acid damage at the start of each of its turns.

If the eye monger takes 25 damage or more on a single turn from a creature inside its gullet, the eye monger regurgitates the swallowed creature, which falls prone in a space within 10 feet of the eye monger. If the eye monger dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 10 feet of movement, exiting prone.

VILLAIN ACTIONS: 

The eye monger has 3 villain actions. They can take each action once during an encounter after an enemy's turn. They can take these actions in any order but can use only one per round. 

Gravitic Lunge.  The eye monger’s body distorts as its central eye dilates, bending space toward its gullet. Each creature within 30 ft must make a DC18 Strength save. On a failure, the creature is pulled up to 20 ft straight toward the eye monger. On a success, the creature is only pulled 10 ft instead. If any creatures are pulled into melee range, the eye monger can make a Bite attack on one of the creatures as a free action.

Antimagic Pulse. The eye monger convulses, expelling waves of nullifying energy from it's gullet. Until the start of the eye monger's next turn, any spells of 5th level or lower, and any magical items (excluding artefacts) within a 30-ft. radius of the eye monger are nullified. Also, any creatures within the 30-ft. radius which are concentrating on a spell must pass a DC18 Constitution save or lose concentration, even if the spell they are concentrating is outside of the 30 ft. radius. 

Regurgitated Horror. The eye monger violently disgorges the partially digested matter of it's victims from across space and time. If a creature is currently swallowed by the eye monger, that creature is hurled out of the eye monger's gullet and thrown 15 ft. in a random direction. That creature takes (5d6) acid damage and (5d6) force damage, and then lands prone. If no creatures are currently swallowed by the eye monger, the eye monger spits a mass of corrosive slurry in a 30 ft. cone. Each creature within the cone must make a DC18 Dexterity save. If they fail the save, they each take (5d6) acid damage and fall prone. If they pass the save, they take half the damage and do not fall prone.