Pearl Forrester is the mother of
Dr. Clayton Forrester, the original
arch nemesis of
Mike Nelson, and earlier,
Joel Robinson, on
MST3K.
Pearl came to Deep 13 in the beginning of Season 7 after TV's Frank was assumed into Second Banana Heaven. She felt that her son needed someone to be with him in his lab. So, she inhabited the lab with him and pestered him for all of Season 7 (All 7 episodes, that is) until Mike and the bots reached the edge of the universe and Clayton turned into a space baby.
She swore that she'd raise Clayton right this time around. But, she got distracted and he went off on his mad quest to take over the world again. On his deathbed (Pearl smothering him to death with a pillow), his final request was that she continue the experiments. She vowed to do whatever it takes to do so.
Five hundred years later, when the Satellite of Love returned to earth, Mike and the bots were suprised to see Pearl alive and well. She explained that she put herself into cryogenic freezing until her disease could be cured. Five hundred years later, the apes which humans evolved into (Planet of the Apes, remember) found her, revived her, cured her freezer burn, and THAT'S why she's their lawgiver.
In her Volkswagon Minibus spaceship, she tailed the Satellite all across time and space (Season 8), stopping at a couple planets and picking up a couple minions along the way, until they wound up back in modern-day earth above Castle Forrester. It was there she lived for two seasons (Seasons 9 and 10).
However, at the end of Season 10, she started screwing around with the Satellite's controls and it began plummeting into the earth. She was forced to abandon the experiments and move on to something else. She was offered the dictatorship of Qatar before the show ended.
One of the unexplained aspects of Pearl is that she seemed to know Crow before seeing him on the Satellite. She called him Arthur and Crow called her Pearl, even before Clayton introduced her.