Symbiont-Regenerating Flesh

Without a host, this appears as an ooze of living flesh.

Regenerating flesh bonds ubiquitously with every soft tissue in the host body like an infection. It provides the host with the ability to regenerate at a rate equal to 1hp at the beginning of every round.  Additionally, the host benefits from an ADVANTAGE against Poison, Disease, Aging, and Death Saving Throws.

It understands Deep Speech but can speak telepathically with its host once bonded. 

Symbiotic Nature - This cannot be removed while you are attuned to it, and you cannot voluntarily end your attunement to it. If you are targeted by a spell that ends a curse, your attunement to it ends, and it leaves your body. Without a host it begins to wither and die within 1d4 days.

Notes: Advantage: Saving Throws, Bonus: Constitution Score, Bonus: Armor Class, sentient creature and incur 2d8 psychic damage