Venom

From Tardis Wiki, the free Doctor Who reference
Venom

Venom was transmitted via snakebites. (TV: Revenge of the Cybermen)

Zygons carried venom sacs in their tongues. (TV: The Day of the Doctor) Similarily, the two-eyed Silurian subspecies possessed venom glands which allowed them to transmit venom via their tongues. (TV: The Hungry Earth)