Boneless

Boneless were a type of undead unique to the Domains of Dread that arose from one or more corpses lacking their skeleton, typically humanoid corpses  though any creature that naturally has, or had, a skeleton could work. There was no known evidence of this type of undead arising on Toril.

Description
Some boneless were capable of assuming a lanky humanoid form. Such forms had long withered limbs, necks that were like flexible cords, and shrunken wrinkled heads, and fetid skin that was of a translucent reddish-brown hue. They were occasionally seen in loose-fitting rags, though these were often stitched directly onto their skin by their master. Such boneless generally moved with a lurching uncertainty, occasionally dropping to all fours for an animalistic sprint.

Other boneless were incapable of taking on a humanoid form and would instead drape themselves upon the frame of a skeleton or zombie.

Abilities
Both types of boneless were incredibly flexible and strong, capable of using the pliability of their bodies to compress themselves and squeeze through small gaps. However, in order to maintain this a boneless needed to be saturated in a body of water once per week. Failure to do so would cause the boneless to stiffen up, lose their grappling prowess, and become especially vulnerable to fire.

Boneless were capable of seeing in areas of total darkness. They were immune to poisons, charm spells, fear spells,  sleep spells, and death magic. Like most undead, they were vulnerable to holy water, holy symbols, and the spell turn undead.

Combat
Boneless that could take on a humanoid form were capable of wielding weapons, but typically slapped foes with their withered hands. Similarly, those who couldn't would simply slam their bodies against foes.

Both those who could and those who couldn't take on a humanoid form were quite adept at grappling opponents, owing to their flexibility. When in their more gelatinous form, the boneless would wrap themselves around their targets, obscuring their vision and obstructing their airways. Upon dying a boneless would detach from anything it was attached to.

Society
Most boneless in the Domains of Dread arose from corpses that had suffered brutal ends, such as being crushed or skinned, while others were brought to life by means of necromancy,  from such things as abattoirs, necromantic slurries, or scraps of failed experiments.

Habitats
Within the Domains of Dread, boneless were notably found in the Realms-relevant domains of Barovia, Har'Akir, and Hazlan.

Languages
A boneless retained the capacity to understand the languages it had known in life, but was incapable of speaking.

Relationships
Boneless were sometimes known to act as servants of Velsharoon, the neutral evil Faerûnian demigod of necromancy.