She was played by the late Susan Tyrrell.
Mona was a bartender at a tavern in Alaska, where Colonel Parker and Sergeant Burrows are planning to do some illegal hunting. After they enter the tavern and learn their motive, Mona sends them to her ex-girlfriend, Jeri Drumbeater, for assistance—before she is shot by Parker while attempting to inform the authorities. It is later revealed that Jeri is in league with a group of savage vampires and plans to kill both Parker and Burrows in a revenge mission. After Parker kills Burrows to save himself, he encounters Mona, who is also revealed as a vampiress. In the episode's near end, the evil Mona flashed her fangs at Parker and continuously attacks him, only to be killed by Parker with a harpoon through her heart.