Amarathine Gel

Perfect Shapechanger. As an action, she can polymorph into any Medium or Large humanoid she has seen or read from a victim’s mind. She can maintain the form indefinitely and gains advantage on Charisma (Persuasion) and Deception checks while shaped.

Engulf (Recharge 5–6). She can suddenly expand to engulf creatures within 5 feet (Dexterity DC 16 save). Engulfed targets are grappled and restrained. She may deal normal acid damage (4d8) or reduced acid damage (2d8) while imposing a powerful Charm effect (Wisdom DC 17). Charmed creatures feel overwhelming pleasure and are reluctant to struggle free. 

Life Drain. While a creature is engulfed or while she is in physical contact (kissing, embracing, etc.) with a willing or charmed creature, she can use her Life Drain as a bonus action. The target takes 5d8 psychic damage. For every 10 points of damage dealt this way, the target loses 1 point of Charisma.

If a creature’s Charisma score is reduced to 0 by this effect, it melts into a plasmatic blob. The blob will transform into a new (weaker) Amarathine Gel in 1d4 days unless the process is interrupted (e.g. by greater restoration, resurrection, or similar powerful magic). 

Mind Reader. She can read surface thoughts of any creature within 30 feet (as the detect thoughts spell). 

Viscous Form. Resistant to non-magical bludgeoning, piercing, and slashing damage. She can move through spaces as narrow as 1 inch without squeezing. 

Split (1/Day). When reduced to half her hit points, she can split into two smaller Amarathine Gels (CR 5 each). One typically flees with absorbed essence while the other fights.

Combat Style

The Amarathine Gel is a master of seduction and ambush. She isolates targets, charms them, and slowly drains them in humanoid form. Only when threatened or ready to finish multiple foes does she expand into a more ooze-like state to engulf them. She is especially dangerous in luxurious or dimly lit environments where her translucent nature lets her blend into reflections or shadows.

Multiattack. The Amarathine Gel makes two attacks: one with her Slam and one with Life Drain (if in contact with a target).

Slam. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (3d6 + 3) bludgeoning damage plus 9 (2d8) acid damage.

Engulf (Recharge 5–6). The Amarathine Gel expands and attempts to engulf creatures within 5 feet of her. Each creature must make a DC 16 Dexterity saving throw. On a failure, the target takes 18 (4d8) acid damage, is grappled and restrained, and is engulfed. While engulfed, the target takes 9 (2d8) acid damage at the start of each of the Gel’s turns. A creature can use its action to make a DC 16 Strength check to escape.

Life Drain (Bonus Action). While a creature is engulfed or the Amarathine Gel is in physical contact with a willing or charmed creature, she can drain its life force. The target takes 5d8 psychic damage. For every 10 points of damage dealt, the target loses 1 point of Charisma.

If a creature’s Charisma score is reduced to 0 by this effect, it melts into a plasmatic blob. The blob transforms into a new (weaker) Amarathine Gel in 1d4 days unless the process is reversed with powerful magic (greater restoration, resurrection, etc.).

Seductive Glimpse. When a creature within 30 feet that can see her makes an attack against her, the Amarathine Gel can force it to make a DC 17 Wisdom saving throw. On a failure, the creature has disadvantage on the attack roll and is charmed by her until the end of its next turn.