You can only function when possessing a humanoid corpse that lacks a head. you can possess any headless corpse that was humanoid, as long as you are within 5ft of it, you can use your action to possess it, when you do so:

• Your size becomes whatever size that creature was
• Your Walk, Crawl, Burrow, Swim, and Fly speed are replaced by whatever speeds that creature had
• You can move and manipulate that body as if it was your own while possessing it
• While possessing a corpse, you gain any benefits that the corpse's race would give it, such as an Elf's immunity to magical sleep, a Duergars natural ability to cast Invisibility or Enlarge/Reduce (at the appropriate levels), or a Dragonborn's Breath Weapon

You can only be damaged while possessing a corpse, when your hit points reach 0 while possessing a corpse, the corpse disintegrates as it hits the ground, and you revert back to your slime form, forcing you to find another headless humanoid body to inhabit

Due to having to possess a corpse to function, you have unique traits, these traits are as follows:

• You are immune to Poison damage and being Poisoned
• You are resistant to Necrotic damage
• You cannot be healed by magic or potions (the mending spell works on you)
• You cannot gain levels of exhaustion
• You are undead and are affected by effects such as Turn undead, when under such an effect, you are forced out of the body you are possessing, however, you may repossess it after the effect ends

Since you must possess a headless corpse, you lack a head. Whenever you possess a corpse, the head is replaced by your gelatinous mass, which features a yellow glow in a star shape that your sole way of expressing facial expressions, additionally:

• You cannot speak, but may understand languages
• You cannot fulfill Verbal Requirements for spells, however, due to your species' innate magical affinity, this only prevents you from fulfilling Verbal Requirements for spells cast from a scroll or other magic item, as you may cast any other spell by replacing any Verbal components with Somatic components

Your size is determined by whatever corpse you're possessing at the moment, as such, it can change. You are tiny size while in your slime form

At higher levels, you have learned how to detach your gelatinous form from your possessed body without severing the connection, as a bonus action, you can separate your slime form from your body, your slime form cannot move more than 60ft from your body and is attached to the neck of your body via a gooey string, while separated, your body is incapacitated and paralyzed but is resistant to all damage. You can reattach to your body by moving within the same space as it