The gemini

The Gemini is a being who inhabits ones body. This is rare occurrence that happens for a variety of reasons and most Gemini can split into two different bodies each capable of independent thought.

Extra Limbed

Your other body has learned to grow limbs from your body creating different effects on your bonus action such as:

Extra Unarmed Attack

Parry (add two to your AC for one attack)

Holding an extra item

Telepathic Bond

Your able to communicate to your other half. This expands to include the secondary host at level 10.

Two Minds One Body

To split your body is taxing on it and as a consequence you take damage equal to your hit dice rounded up. You then use your character sheet for both bodies.

Inhabit Host

You can perform a grapple check Str versus Str/Dex save to inhabit an opponent. you don't have full control and they can still move of their own volition. your only ability is to protrude limbs from their body. You take on the hosts health and when it gets injured you get injured.

You are able to Telepathically communicate with your new host.

Total Organ Failure

your opponent must make a Con-check equal to your spell save dc. If the check succeeds they take 10d10 damage if not they drop to 0 hit points.