Ceti eels were creatures that lived under the sand on the desert planet in Star Trek II: The Wrath of Khan. They are small and spade shaped with numerous segments, legs and a single pair of eyes. The villain Khan uses Ceti eels as instruments of torture and mind control. Their larvae are pulled from under the adults body plates inserted into a victim's ear, where the Ceti eel attaches itself to the brain stem, causing suggestibility and extreme pain, madness or death. This trick was used on a starfleet officer, captain of the USS Reliant and his first officer, Chekov. It allowed Khan to control them and set a trap for Kirk whom he blamed for his wife's death. She and 19 of Khan's crew were killed by these creatures after the Enterprise marooned them in the Ceti Alpha system.