Your Constitution score increases by 2.

You can change your form to copy any living creature you have studied for at least half an hour, and is medium sized. You may also create your own form, but this requires an Intelligence check with a DC of 18. When in this form you are perfectly identical by looks and sound. This can be done as per of a short or long rest, as long as there is an in memorized creature nearby.

You have a limited amount of forms equal to your Intelligence modifier (minimum of 1). The DM may also allow you to have your own personal form at the start of your journey.

You are able to reattach any body parts that become dismembered, including your head. You are also capable of controlling body parts that are detached, but they can only move 5ft. per action, and can not do any large actions such as attacking, but can do small things like pull a lever. 
You are also capable of detaching body parts as an action. These body parts can only move or complete tasks as a part of your turn, using an action. The detached limb has an AC equal to 10+ your Dexterity modifier, and an HP equal to one hit die+ your Constitution modifier. If a limb were to reach 0 HP, it will become immobile until you reattach it. If your head is detached, it has your current HP, and if it ever reaches 0, your body and limbs all fall still as your are now unconscious.

You are capable of moving through gaps that are at least 5in. wide, but this does not bring items that won’t normally fit through that space.

You also gain resistance to bludgeoning damage.