Fin Symbiote

This tendril of flesh harvested from a living aboleth can be embedded into the skin of an aberrant horror. To attune to this item, you must stitch it onto your skin and leave it for the entire attunement period, during which the fin burrows into your body to bond with your muscular system. While attuned to this item, you gain a +2 bonus to the saving throw DC of your Transformation Save. The fin cannot be removed while you're attuned to it, and you can't voluntarily end your attunement to it. If the tentacle is sliced from your body, it grows back in 1d4 hours.