Medusoid

The Medusoids were a race of aliens, described by the Third Doctor as looking like "some sort of hairy jellyfish, with claws, teeth and a leg."

The Doctor was once captured en route to the Third Intergalactic Peace Conference by Medusoids. They used several mind probes on him in an attempt to find out where he was going. The Doctor shorted out every one of the Medusoids' probes (by telling them, "I'm on my way to meet a giant rabbit, a Pink Elephant and a purple horse with yellow spots."), forcing them to release him. (TV: Frontier in Space)