Alchemuffet

Spider Traits. The spider can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check. While in contact with a web, the spider knows the exact location of any other creature in contact with the same web. The spider ignores movement restrictions caused by webbing.

Mutable Form. If the spider is forcibly transformed, roll 1d6 once it returns to normal. Depending on the results of the roll, one of its attribute scores is permanently replaced by the same attribute score of the creature it was transformed into (no more than +1 or -1 from its original score per transformation).

Boiling Aura. A creature that ends its turn within 20 ft of the spider takes 6 (2d6) fire damage. If a creature hits the spider with an unarmed attack, it takes this damage again. If a creature within 20ft of the spider takes acid damage, it then takes an additional 3 (1d6) fire damage. A creature making a weapon attack against the spider may choose to bypass the nonmagical damage resistance, but doing so will cause the weapon to take 6 (2d6) fire damage.

Multiattack. The spider makes three attacks: one with its bite, and two with its web against different creatures.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 13 (2d8 + 4) piercing damage, and the target must make a DC 15 Constitution saving throw, taking 19 (3d12) poison damage on a failed save, or half as much damage on a successful one. If any poison damage dealt by this attack reduces the target to 0 hit points, the target is stable but poisoned for 1 hour, even after regaining hit points, and is paralyzed while poisoned in this way.

Searing Web. Ranged Weapon Attack: +7 to hit, range 30/60 ft., one creature. Hit: The target takes (1d6) acid damage and is restrained by webbing. At the end of each of its turns, the restrained creature takes an additional (1d6) acid damage. As an action, the restrained target can make a DC 15 Strength check, bursting the webbing on a success. The webbing can also be attacked and destroyed (AC 12; hp 10; immunity to bludgeoning, fire, acid, poison, lightning, and psychic damage).