Charmed (1998): Season 8, Episode 4

8 - 4: Desperate Housewitches

Wyatt's school play brings out the competitive nature in Piper when her hand-sewn costume & parenting abilities are criticized by another mother. However things go from bad to worse, because this Stepford-like mother is actually a demon in disguise bent on kidnapping Wyatt in a plot to resurrect the Source. Meanwhile, Paige spies Dex with another woman, and despite Phoebe's objections, butts in.