Crystalline Symbiote

Symbiotic Being. A crystal growth that takes the form of the kargat police badge, but can change to other objects on your body according to its will.

Your symbiote is a separate entity with its own physical form bound to yours. It isn’t a separate creature and relies on you to survive. It has:
Intelligence: 12
Wisdom: 6
Charisma: 16

The symbiote speaks, reads, and understands Common and Infernal

You gain proficiency in Investigation.

If you die, so does your symbiote. If you are subsequently returned to life, your symbiote revives as well.

Sustained Symbiosis. Your symbiote has a vested interest in your survival and takes steps to ensure it. When you fail a saving throw, you can choose to have your symbiote expend one of your Hit Dice to roll it and add the number rolled to the saving throw, potentially turning the failure into a success. If it uses this feature on a death saving throw, you succeed on the save and regain 1 hit point regardless of the number rolled on the d20.

Once you succeed on a saving throw due to this trait, the symbiote can’t use it again until you finish a long rest.

Symbiotic Agenda. The symbiote seeks to experience new sensations, the more bizarre the better, and it expects you to assist it in achieving those. DM will decide how permissive or patient it is in resolving its agenda depends on its personality. If you have an opportunity to advance its agenda and don’t act on it, the symbiote can try to force your hand. You must succeed on a Charisma saving throw (DC 12 + the symbiote’s Charisma modifier) or be charmed by the symbiote for 1d12 hours. While charmed, you must try to follow the symbiote’s commands. If you take damage that is not self-inflicted, you can repeat the saving throw, ending the effect on a success.