Pyschospore

A psychospore, alternatively spelled psychospoor (PROSE: The Pirate Planet) and referred to as a psychic spore, (AUDIO: Signs and Wonders) was a trace of someone's mind, as psychokinetic energy on a high level of the Vantalla Psychoscale left considerable disturbance in the ether. (TV: The Pirate Planet)

Although he escaped them physically, Praska of the Aquillians was able to track the Seventh Doctor's psychic spore because it was so potent, enabling her to telepathically communicate with him. (AUDIO: Signs and Wonders)

K9 Mark II tracked Romana II on Aoris by her psycho-spore. (AUDIO: The Paradox Planet)