MOM is a supporting character of Martin Mystery. Her real name is unknown, though she used the alias Ms. Olivia Mandell (derived from the initials M.O.M.) in the episode "Web of the Spider Creature".
She is voiced by Teryl Rothery who is best known for voicing as Kodachi Kuno from Ranma ½ Seasons 1-4.
M.O.M. is usually a strict, serious, and uncompromising woman who's rarely been known to show her humorous side. One possible source of her anger is how often she is mad at Martin for ruining, blowing up or tampering with her experiments and every piece of gadgetry that she's working on due to his immature behavior and whenever he appears for a debriefing in her office.
Despite her typically dry sense of humor, she is actually quite- as Billy says- "a real party animal." M.O.M is often seen as being harsh and authoritative with her employees, especially Martin Mystery. Nevertheless, M.O.M. is shown to care for her agents and have a strong sense of responsibility.
As the multi-tasking director and the head of "The Center", M.O.M. oversees the investigation of paranormal activities throughout the world. Martin's capabilities make him one of her favorite agents - if "favorite" is meant by "the agent that she would rather spend the most time with in the field and out of her office". Also, she is in charge of maintaining peace with Earth and other planets and galaxies.
It is often hinted throughout the show that M.O.M. might be somewhat of a workaholic by the fact that she was forced to take up a hobby and has never taken a sick day. Her life outside of the Center is also unknown.
- She is shrunk by Martin in Return of the Dark Druid when he drops the shrink ray.
- In Attack of the Evil Roommate, a friend of hers at the World Space Agency named a star after her.
- The initials M.O.M. are said to actually stand for "Mystery Organization Manager", as explained by Martin.