Scorpion

Scorpions, relatives of spiders, were a type of arachnid with powerful claws and a venomous sting in their tail.

The Tong of the Black Scorpion was a criminal organisation on Earth whose members all had scorpion tattoos on their hands. To avoid giving up information about their organisation they were expected to swallow a pill containing scorpion venom. (DW: The Talons of Weng-Chiang)

A species of cave-dwelling scorpion was native to the planet Karagula.

An intelligent race of giant scorpions formed after the extinction of Earth's dinosaurs were led by the Scorpion King, who taught them to recite Block Transfer Computations. (BFA: The Boy That Time Forgot)

The Xaranti were a scorpion-like race. (PDA: Deep Blue)

Richard Lazarus was transformed into a scorpion-like creature as an unintended side-effect of his Genetic Manipulation Device. (DW: The Lazarus Experiment)

Black scorpi were scorpion-like creatures native to an unnamed planet. (TVC: Plague of the Black Scorpi)