Broodmother's Embrace (Legendary)

This thick, rubbery overcoat sports several writhing tentacles that can biomantically fuse with their wearer, acting as gills, propulsion, and a formidable, concealed weapon. When in danger, the coat can encapsulate you in a protective chrysalis, nourishing you with stored regenerative mucous. While wearing the coat underwater, tentacles wrap around your throat, fusing with your vascular system and allowing you to breathe underwater. The tentacles also propel you, giving you a swimming speed of 60 feet. The coat's many eyes enhance your peripheral vision; while wearing the coat you have advantage on initiative checks while not blinded.

Tentacle Lash: As an action, you can make a melee spell attack (+9 to hit) against a creature within 20 feet of you. On a hit, the creature takes 5d8 bludgeoning damage, and, if it is Large or smaller, must make a DC 17 Strength saving throw or be knocked prone.

Chrysalis: You can use an action to cause the coat to expand and harden, encasing you in a regenerative, chitinous casing which grants you 60 temporary hit points. While encased, your speed is reduced to 0 feet, you can't take actions or reactions (except the action to emerge from the chrysalis), and you regain 6d6 hit points at the start of each of your turns. You can regain no more than 90 hit points in this way while encased. These effects end when the temporary hit points are lost, after 1 minute, or when you decide to emerge from the chrysalis as an action, whichever comes first. After you activate this property, you can't do so again until the next dawn.