The Stillman Sisters were a trio of witches who used dark magic against the Charmed Ones in Charmed.
The Stillman sisters were witches but abused their powers by willfully using dark magic for crimes; they were known for committing magical crimes and were wanted in several states such as California.
In the episode, they are introduced as the Charmed Ones breaking into the attic to steal the Book of Shadows but it scoots away from them. They are Margo, Mitzy, and Mabel. Mitzy and Margo go on about the plan not working but Mabel says that things will always work out. First, they need to take on the identities of the Charmed Ones. Then steal the Book. They hear Paige coming in so they teleport out of the house.
Later, the sisters move into a house across from the Charmed Ones, killing the inhabitants. They then view the Halliwell sisters through a scrying bowl and Margo says how she wants to throw Wyatt, Paige's son, into a volcano.
Afterward Mitzy goes on about how she wants Phoebe's white-lighter powers and how she never gets anything good. She says she wants the best powers and how Piper's powers will suck. Mitzy and Margo get into a fight but then Mabel comes to break it up by killing a salesman who came to sell them a new hoover. At this, Margo feels guilty at provoking her sister so, showing her love for her, she hugs Mitzy and tells her that once she gets the Whitelighter powers, she is willing to do anything for Mitzy. A delighted Mitzy agrees, and a gleeful Margo reminds her sisters that once they have the Book they'll be all powerful.
In the afternoon they perform the dark spell to steal the identities of the Halliwells, which goes something like this:
Blinking faces, bland and ho-hum. We are they and they are no one Grant to us the power of three And turn them into nobody
To prove it worked, Mabel summons Chris the white-lighter who has to do the Halliwell's bidding. He thinks the Stillmans are the Halliwells. This delights the evil witches. The Stillmans tell Chris to orb to the Astral Plane because of a knife they used to kill the salesman but Mabel pretends a demon did it.
After successfully compelling Chris to do their bidding, Mabel cheerfully announces to her younger sisters that they are now "Charmed and dangerous!" to which Mitzy says "Oh yeah" and they all begin doing a little victory dance which involves slapping each other's hands in victory
Chris later finds out they lied to him but they try and seduce him but it doesn't work. Chris begins to suspect they may not be the Halliwells. He finds the Halliwells who have been kicked out of their jobs after their ID cards showed the Stillman sisters as their employees instead.
Chris manages to get the Halliwells to their house where the Stillmans are poring over the Book to get an entry. They do, but its a very small entry. It just says use a binding spell to imprison the sisters, not kill them because they are unworthy of being killed. The Stillmans are offended by this.
The Halliwells show up and fight the Stillmans but the Stillmans win and Margo gets angry when she can't orb but Paige can. Later the Halliwells meet the Stillmans and have a showdown when they manage to make Margo think Mitzy hates her and make the sisters fight. The Halliwells subdue the Stillmans and get back their powers. Then they turn the Stillmans over to police for murder.
- Margo, the youngest, is a clear coward, and she would rather be with her sisters than engage in ambitions, this is proven when she says the plan is dangerous, and also the way she embraces Mitzy's naked back suggests she is holding her for protection.
- Mabel seems to be the evilest of the group because she has no qualms about killing or abusing anyone, friend or foe, making her a clear sociopath.