Britesor

Gummifying Gaze. When a creature that can see Britesor's eyes starts its turn within 30 feet of her, Britesor can force it to make a DC 14 Constitution saving throw if she is not incapacitated and can see the creature. If the saving throw fails by 5 or more, the creature is instantly petrified. Otherwise, a creature that fails the save begins to turn to a gummy version of themself and is restrained. The restrained creature must repeat the saving throw at the end of its next turn, becoming petrified on a failure or ending the effect on a success. The gummy petrification lasts until the creature is freed by the greater restoration spell or other magic.

Unless surprised, a creature can avert its eyes to avoid the saving throw at the start of its turn. If the creature does so, it can't see Britesor until the start of its next turn, when it can avert its eyes again. If the creature looks at her in the meantime, it must immediately make the save.

If Britesor sees herself reflected on a polished surface within 30 feet of her and in an area of bright light, she is affected by her own gaze.

Spellcasting. Britesor is a 10th-level spellcaster. Her spellcasting ability is Charisma (spell save DC 15, +7 to hit with spell attacks). Britesor has the following sorcerer spells prepared:

Cantrips (at will): 4 Thunderclap, Blade Ward, Chill Touch, Eldritch Blast
5th level (2 slots): Far Step, Control Water

Ascendant Step. She can cast levitate on herself at will, without expending a spell slot or material components.

One with Shadows. When she is in an area of dim light or darkness, she can use her action to become invisible until she moves or takes an action or a reaction.

Thirsting Blade. Britesor can attack with her pact weapon, a whip, twice whenever she takes the attack action on her turn. 

Multiattack. Britesor makes either three melee attacks--one with her gummy worm hair and two with her whip--or two spell attacks.

Gummy Worm Hair. Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 4 (1d4 + 2) bludgeoning damage.

Whip. Melee Weapon Attack: +5 to hit, reach 10 ft., one creature. Hit: 5 (1d4 +3) slashing damage.

Tentacle of the Deep. Britesor can magically summon a spectral tentacle that strikes at her foes.

• As a bonus action, Britesor creates a 10-foot-long tentacle at a point she can see within 60 feet of her. The tentacle lasts for 1 minute or until she uses this feature to create another tentacle. When she creates the tentacle, she can make a melee spell attack against one creature within 10 feet of it. On a hit, the target takes 2d8 cold damage, and its speed is reduced by 10 feet until the start of her next turn.
• As a bonus action, she can move the tentacle up to 30 feet and repeat the attack. She can summon the tentacle a number of times equal to her proficiency bonus.

Guardian Coil. When Britesor or a creature she can see takes damage while within 10 feet of the Tentacle of the Deep, she can use her reaction to choose one of those creatures and reduce the damage to that creature by 2d8.

Grasping Tentacles. Britesor can cast the spell Evard's Black Tentacles once without using a spell slot. Whenever she casts this spell, Trolli's magic grants her 10 temporary hit points. Moreover, damage can't break her concentration on this spell.