Lethean

Letheans are a sapient humanoid species known for their ability to attack others telepathically and probe their victims' minds to steal information and memories.

Biology
Letheans are humanoids with ridged, hairless skin, blood-red eyes and sharp teeth. Their hands have five fingers, with a long claw on their thumbs and spikes on their base knuckles. They attack by holding a victim's head with both hands and releasing electrical discharges from their palms, which place the victim into an unconscious state while the Lethean probes their mind in search of information.

Lethean telepathic attacks are nearly almost fatal. In some cases, victims have been known to experience dream-like hallucinations while unconscious. Others, however, have been known to wake up with no memory of even being attacked in the first place, as was the case of the Klingon Kor, although this might have to do with the fact that Kor was attacked while drunk.

Appearances

 * Star Trek: Deep Space Nine
 * s03e18, "Distant Voices" (1995)
 * s04e09, "The Sword of Kahless" (1995)