Zygons

The Zygons were a race of metamorphic humanoids. They originated from the planet Zygor, but often tried to migrate away from it. (PROSE: The Bodysnatchers)

Zygons were solidly built humanoids with large, cone-shaped heads. Their heads, arms and torsos were covered in suckers, and they had deeply inset faces. Zygons had dark red blood and spoke in a gurgling whisper. They were stronger than humans and apparently more long-lived, their lifespan continuing over Earth centuries. (TV: Terror of the Zygons) They also had an earthy, iron odour and the ability to sting people with venomous barbs on their palms. These stings could stun, maim or kill. They left large welts on the affected area. (PROSE: Sting of the Zygons, Doctor Who and the Loch Ness Monster) They also had the ability to transform members of other species into Zygons, with the side effect of creating a telepathic link between the new Zygon and the one that induced the change. (HOMEVID: Zygon: When Being You Just Isn't Enough)

They had venom sacs located in their tongues. (TV: The Day of the Doctor)