A Clinging Glow is really a cloud of unusually predatory plankton. While many ocean creatures have learned to sense its draining presence and avoid it, it still obtains plenty of prey and can prove deadly to creatures that don’t belong in the sea.
Huge Cloud, Unaligned
Armor Class: 8
Hit Points: 9 (2d8)
Speed: 20 ft. swim
|6 (-2)||6 (-2)||10 (+0)||1 (-5)||8 (-1)||4 (-3)|
Damage Immunities: psychic, bludgeoning, piercing, slashing
Damage Resistances: fire, cold
Condition Immunities: charmed, frightened, grappled, paralyzed, petrified, prone, restrained, stunned
Senses: passive Perception 9
Challenge: 1/8 (25 XP)
Cloud. Other creatures can freely enter, pass through, and leave spaces occupied by the clinging glow.
Entrancing Glow. Whenever a creature moves within a space occupied by the clinging glow, lights shimmer around it. The creature must make a DC 13 Wisdom Save or be entranced to stay in the cloud with the lights. They may make a new on their turn to attempt to move out of the cloud.
Energy Drain. All creatures sharing a space with the clinging glow suffer 1 damage.
My Tyranny of Mundanity players met these recently. It was a bit of work to get away.