Medusa (species)

The Medusas were a predatory alien species. The Fourth Doctor described them as vile. A Medusa was able to quantum-lock a person, making them petrified.

People who had been petrified were, however, still alive, frozen in time, preserved, so the Medusa could feed on their life energy for years, centuries, even. When the Medusa was done feeding, the petrified person turned to dust.

One Medusa was hunted by Zeus and his spacefaring people, who referred to her only as Horror; she hijacked their spaceship, crashing it into ancient Greece, where they became known as Medusa and the Greek gods. (COMIC: Gaze of the Medusa)

Biology
The Medusas were reptilian humanoids. They had dark green scaly skin, black hair, sharp claws, large jaws and a massive tail in place of legs. (COMIC: Gaze of the Medusa)

Powers and abilities
Medusas were capable of quantum-locking. However, unlike the Weeping Angels who petrified themselves as a defence mechanism, the Medusas quantum-locked their prey. They emitting a beam of blue light from their eyes; anything caught in its path was turned to stone. The victim was preserved indefinitely, immune to the effects of time, allowing the Medusa to feed off their life energy over centuries. Victims could sometimes be only partially petrified, in which case their movement was hindered, and they could be smashed and killed as they slowly, painfully turned to stone.

The Medusas also had potent telepathic powers, and could easily mentally control humans or Scrylops. They could also transfer their consciousness into a body of another species, though the victim had to be prepared gradually by a special process of partial petrification. The host was finally quantum-locked, and then the Medusa emerged, having biologically modified the host's body into a new form similar to a Medusa. (COMIC: Gaze of the Medusa)