Berbayerbalang
A horrifying, fish-eating monster that roams the central island of Murlocke’s personal pocket dimension, known as Murlocke’s Super Happy Fun-World. It guards the plane’s central island, home to the people Murlocke sent there on personal affairs. It is a freakish creature known to the pocket dimension’s locals from Murlocke as the berbayerbalang.
It mercilessly devours any fish seen trying to exit the ocean, using its keen smell to sense them and wings to quickly converge on the prey.
Berbayerbalang
INT 3 (-4) WIS 11 (+0) CHA 9 (-1)
Legendary Resistance (5/Day). If the berbayerbalang fails a saving throw, it can choose to succeed instead.
Banishment Immunity. The berbayerbalang is immune to the effects of the Banishment spell and automatically succeeds any saving throw against it getting magically teleported or shifted to a different location, such as by Plane Shift or Teleport.
Indomitable Form. The berbayerbalang is immune to any spell or effect that would alter its form. Additionally, it gains an advantage on saving throws against becoming possessed.
Keen Senses. The berbayerbalang gains an advantage on any Wisdom (Perception) checks that rely on smell or sound.
Magic Weapons. The berbayerbalang’s attacks are counted as magical.
Multiattack. The berbayerbalang can use its Frightful Presence. It then makes three attacks: one with its bite and two with its claws.
Bite. Melee Weapon Attack: +19 to hit, reach 10 ft., one target. Hit: 36 (4d12 + 10) piercing damage, and the target has the grappled condition (escape DC 22). Until the grapple ends, the target has the Restrained condition and can’t teleport.
Claw. Melee Weapon Attack: +19 to hit, reach 10 ft., one target. Hit: 28 (4d8 + 10) slashing damage.
Frightful Presence. Each creature of the berbayerbalang 's choice that is within 120 ft. of and aware of it must succeed on a DC 26 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 or the effect ends for it, the creature is immune to the berbayerbalang's Frightful Presence for the next 24 hours.
Hypnotic Scream (Recharge 3-4). The berbayerbalang unleashes an ear-piercing, horrible wail audible to all creatures in a 20-mile radius. Each creature standing within 120 feet of the berbayerbalang must make a Wisdom saving throw (DC 18). On a failed save, a target takes 4d8 psychic damage and is stunned. On a successful save, a target takes half as much damage and isn’t stunned. If a target is killed by this damage, its head explodes, assuming it has one. A stunned target can make an Intelligence saving throw at the end of each of its turns. On a successful save, the stunning effect ends.Swallow. The berbayerbalang 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 has the Blinded and Restrained conditions and can’t teleport, it has total cover against attacks and other effects outside the berbayerbalang, and it takes 42 (12d6) Acid damage at the start of each of the berbayerbalang's turns. If the berbayerbalang takes 75 damage or more on a single turn from a creature inside it, the berbayerbalang must succeed on a DC 20 Constitution saving throw at the end of that turn or regurgitate all swallowed creatures, each of which falls in a space within 10 feet of the berbayerbalang and has the Prone condition. If the berbayerbalang dies, any swallowed creature no longer has the Restrained condition and can escape from the corpse using 20 feet of movement, exiting Prone.
The berbayerbalang can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. The berbayerbalang regains spent legendary actions at the start of his turn.
Detect. The berbayerbalang makes a Wisdom (Perception) check.
Claw. The berbayerbalang makes a claw attack.
Heat Vision (Costs 2 Actions). The berbayerbalang swipes a ray of heat vision in a 120-foot cone. Each creature in that area must make a DC 25 Dexterity saving throw, taking 54 (12d8) Fire damage on a failed save, or half as much damage on a successful one.