Atmospheric Jellyfish

Clear Body. At the start of each of its turns, if the atmospheric jellyfish is affected by a condition, it immediately recovers from the condition. If it is affected by multiple conditions, the atmospheric jellyfish can only recover from one condition at a time.

Transparent. Even when the atmospheric jellyfish is in plain sight, it takes a successful DC 15 Wisdom (Perception) check to spot a jellyfish that has neither moved nor attacked. A creature that tries to enter the jellyfish's space while unaware of the cube is surprised by the jellyfish.

Multiattack. The atmospheric jellyfish makes two attacks.

Stinger. Melee Weapon Attack. +5 to hit, reach 5 ft., one creature. Hit: 20 (6d6) poison damage, and the target must make a DC 15 Constitution saving throw. On a failure, the target is poisoned for 1 hour.

Pseudopod. Melee Weapon Attack. +5 to hit, reach 10 ft., one creature. Hit: 20 (6d6) acid damage.

Engulf. The atmospheric jellyfish moves up to its speed. While doing so, it can enter Large or smaller creatures' spaces. Whenever the atmospheric jellyfish enters a creature's space, the creature must make a DC 15 Dexterity saving throw.

On a successful save, the creature can choose to be pushed 5 feet back or to the side of the atmospheric jellyfish. A creature that chooses not to be pushed suffers the consequences of a failed saving throw.

On a failed save, the atmospheric jellyfish enters the creature's space, and the creature takes 10 (3d6) acid damage and is engulfed. The engulfed creature can't breathe, is restrained, and takes 21 (6d6) acid damage at the start of each of the jellyfish's turns. When the atmospheric jellyfish moves, the engulfed creature moves with it.

An engulfed creature can try to escape by taking an action to make a DC 15 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the atmospheric jellyfish.