Beckoning Maw

Legendary Resistance (3 / Day). If the Beckoning Maw fails a saving throw, it can choose to succeed instead.

Spell Turning. Whenever the Beckoning Maw is targeted by a spell, roll 1d6. On a 1, the spell takes normal effect. On a 2-3, nothing happens and the spell slot is wasted. On a 4-5, the spell has no effect and the Beckoning Maw recharges all of its abilities. On a 6, the spell has no effect, the Beckoning Maw recharges all of its abilities, and the caster of the spell is targeted instead.

Camouflage. As long as the Beckoning Maw does not move or open its mouth, it requires a DC15 intelligence (investigation) check from at most 15ft away to discern that it is not just a very, VERY large boulder.

Frightful Presence. Each creature of the Beckoning Maw's choice that is within 120 feet of it and aware of it must succeed on a DC 19 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful, the creature is immune to the Beckoning Maw's Frightful Presence for the next hour.

Infectious Breath (Recharges 4-6). Up to 6 creatures of the Beckoning Maw's choice within 60 feet of its mouth must succeed on a DC 19 Constitution saving throw or become diseased. The disease has no effect for 1 minute and can be removed by any magic that cures disease of 6th level or higher. After 1 minute, the diseased creature’s skin becomes translucent and slimy, the creature can’t regain hit points, and the disease can be removed only by wish. When the creature is not on the astral plane, it takes 19 (3d12) acid damage every 10 minutes, and its hit point maximum is reduced by the same amount. This reduction lasts until the creature dies or until the disease is cured. The target dies if its hit point maximum is reduced to zero.

Swallow. The Beckoning Maw makes one bite attack against a Large or smaller creature it is grappling. If the attack hits, the target takes the bite’s damage, the target is swallowed, and the grapple ends. While swallowed, the creature is blinded and restrained, it has total cover against attacks and other effects outside the Beckoning Maw, and it takes 56 (16d6) acid damage at the start of each of the Beckoning Maw's turns.

If the Beckoning Maw takes 80 damage or more on a single turn from a creature inside it, the Beckoning Maw must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, which fall prone in a space within 10 feet of the Beckoning Maw. If the Beckoning Maw dies, a swallowed creature is no longer restrained by it and can escape from the corpse by using 30 feet of movement, exiting prone.

Bite. Melee Weapon Attack: +14 to hit, reach 15 ft., one target. Hit: 196 (8d20 + 112) piercing damage plus 9 (2d8) cold damage, and the target is grappled if it is.

Beckon (5 / Day). One creature withing 80ft of the Beckoning Maw must succeed on a DC 19 wisdom saving throw or be charmed by the Beckoning Maw for 1 minute. Whilst charmed, the creature is incapacitated and must spend all of its movement trying to get within 5ft of the Beckoning Maw. Once it is within 5ft of the Beckoning Maw, it is paralysed until it dies or is no longer within 5ft of the Beckoning Maw.

Summon Will-o'-Wisps (Recharges after a Short or Long Rest). The Beckoning Maw magically creates 4d4 lawful evil Will-o'-Wisps if it isn't in bright light. The Will-o'-Wisps regard the Beckoning Maw as their master, but are not under its control.

Beckon. When the Beckoning Maw takes damage from an attack, it can use Beckon on the creature that attacked it.