b'Gulper Behemoth \n'b'  Gargantuan   monstrosity ,  unaligned  \n'b'  Armor Class  16 (natural armor)  Hit Points  188 (13d20 + 52)  Speed  0 ft., swim 40 ft.\n'b' STATS STR: 20 (+5) DEX:  10 (+0)  CON:  19 (+4)  INT:  4 (-3)  WIS:  10 (+0)  CHA:  5 (-3)  \n'b'\n'b'\n'b'\n'b'\n'b'\n'b'\n'b'  Damage Vulnerabilities  piercing  Damage Resistances  acid, thunder  Condition Immunities   blinded   Senses   blindsight  120 ft., passive  Perception  10  Languages  \xe2\x80\x93  Challenge  9 (5,000 XP) \n'b' Special Traits \n'b'\n'b'  Death Burst . The gulper behemoth explodes when it drops to 0  hp . Each creature within 40 feet of it must succeed on a DC 16  Constitution  saving throw, taking 21 (6d6) acid damage on a failed save. \n'b'  Echolocation . The gulper behemoth can\xe2\x80\x99t use its  blindsight  while deafened. \n'b'  Keen Hearing . The gulper behemoth has advantage on  Wisdom  ( Perception ) checks that rely on hearing. \n'b'  Water Breathing . The gulper behemoth can breathe only underwater. \n'b'\n'b' Actions \n'b'\n'b'  Bite .  Melee Weapon Attack : +9 to hit, reach 10 ft., one target.  Hit : 40 (6d10 + 7) piercing damage. If the target is a creature, it is  grappled  (escape DC 16). Until this grapple ends, the target is  restrained , and the gulper behemoth can\xe2\x80\x99t bite another target. \n'b'  Swallow . The gulper behemoth makes one bite  attack  against a Large or smaller creature it is grappling. If the  attack  hits, the creature is also swallowed, and the grapple ends. While swallowed, the creature is  blinded  and  restrained , it has total  cover  against attacks and other effects outside the behemoth, and it takes 14 (4d6) acid damage at the start of each of the behemoth\xe2\x80\x99s turns. If the gulper behemoth takes 20 damage or more on a single turn from a creature inside it, the behemoth must succeed on a DC 15  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 behemoth. If the behemoth dies, a swallowed creature is no longer  restrained  by it and can escape from the corpse by using 15 feet of movement, exiting  prone . \n'b'  Sonic Pulse (Recharge 5-6) . The gulper behemoth expels a sonic pulse in a 60-foot cone. Each creature in that area must make a DC 16  Constitution  saving throw. On a failure, the creature takes 21 (6d6) thunder damage and is stunned until the end of its next turn. On a success, the creature takes half the damage and isn\xe2\x80\x99t stunned. \n'b'\n'b' The titanic eel-like creature has delicately dancing frills and flickers of phosphorescence just under its translucent skin. Its mouth opens impossibly wide as it surges forward. \n'b'  Deep Sea Lure . The gulper behemoth lives in the waters of the remotest oceans. It lures sea dwellers to their deaths with dancing motes of light within its massive, ballooning gullet. Rumors abound that even a sharp pinprick will deflate the sea monster. \n'b' Lair &amp; Lair Actions \n'b' The gulper\xe2\x80\x99s lair is filled with brightly-colored and labyrinthine giant corals. Smaller, mutualistic predators swim throughout the lair, keeping it well protected. \n'b' On  initiative  count 20 (losing  initiative  ties), the gulper behemoth takes a lair action to cause one of the following effects; the gulper behemoth can\xe2\x80\x99t use the same effect two rounds in a row: \n'b'\n'b' The gulper behemoth commands deep sea eels and plants to constrict a target it can see within 60 feet of it. The target must succeed on a DC 15  Strength  saving throw or be  restrained  until  initiative  count 20 on the next round. \n'b' The gulper behemoth commands plants and coral to shoot boiling water at up to three creatures it can see within 60 feet of it. Each target must make a DC 15  Constitution  saving throw, taking 10 (3d6) fire damage on a failed save, or half as much damage on a successful one. Being underwater doesn\xe2\x80\x99t grant  resistance  against this damage.'