16 (natural armor)
200 (16d12 + 96)
40 ft., swim 40 ft.
Perception +7, Stealth +7
charmed
darkvision 90 ft.
-
15
The cave hydra can breathe air and water.
While in sunlight, the cave hydra has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.
If the cave hydra moves at least 20 ft. straight toward a target using its tentacles and then hits with one of its tentacles on the same turn, that one target takes an extra 9 (2d8) bludgeoning damage. If the target is a creature, it must also succeed on a DC 18 Strength saving throwor be knocked prone.
The cave hydra makes five attacks with its tentacles or one bite attack.
Melee Weapon Attack: +11 to hit, reach 15 ft., one target. Hit: 15 (2d8 + 6) bludgeoning damage and the target is grappled (escape DC 18). Until this grapple ends, the target is restrained and has disadvantage on Strength checks and Strength saving throws, and the cave hydra can't use the same tentacle on another target. The cave hydra has five tentacles, each of which can grapple one target.
Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 17 (2d10 + 6) piercing damage.
The cave hydra makes one bite attack against a Medium or smaller target it is grappling. If the attack hits, the target is swallowed, and the grapple ends. The swallowed target is blinded and restrained, it has total cover against attacks and other effects outside the hydra, and it takes 21 (6d6) acid damage at the start of each of the cave hydra's turns. A cave hydra can have only one target swallowed at a time. If the cave hydra dies, a swallowed creature is no longer restrained by it and can escape from the corpse using 15 feet of movement, exiting prone.