Scorpion

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

History
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. (AUDIO: The Boy That Time Forgot)

In 1400 BC, Peri Brown and Erimem were almost attacked by thousands of scorpions sent by Yanis, but they managed to escape. (AUDIO: The Eye of the Scorpion)

In India in 1947, the Tenth Doctor and Donna Noble were menaced by scorpions which had been mutated by zytron energy, but the Doctor drove them off with his sonic screwdriver. (PROSE: Ghosts of India)

Scorpion-like species
Richard Lazarus was periodically mutated into a scorpion-like creature at random intervals as an unintended side-effect of his Genetic Manipulation Device. (TV: The Lazarus Experiment)

Scorpionkind were a species of predatory animal on New Earth. (AUDIO: The Cats of New Cairo)

The Skithra attempted to abduct Nikola Tesla, so that he could repair their stolen technology. (TV: Nikola Tesla's Night of Terror)