Dracolich

Dragons live a long time, but they still die. dragons that choose not to- instead using dark rituals to allow negative energy to consume them, Binding their souls to a precious gemstone and taking on many of the properties of a lich.

Due to their innately evil nature, dracoliches tend to be of chromatic dragon stock, and look mostly like they did in life- just mouldier or skeletal. Dracoliches retain all of their living abilities (like breath weapons, flight, frightful presence, and so on) but gain all of the usual undead immunities and vulnerabilities (poison, charm, paralysis, etc.). Most DMs will also throw in the ability to control undead too- they are a Lich after all, and what self respecting undead dragon-lord doesn't want an entourage of utterly dominated dragon-guard wights?