Attack of the Demon Dinner Ladies
Izzy and her friends have never liked school dinners. And they're getting worse. The dinner ladies are acting strangely (making up random rules, wearing hats, and cooking new food, even more horrible than usual).
Lollipop man mentions there is a new head dinner lady and calls her "a bit of a legend" (in a bad way) and that she used to be here a long, long time ago and has returned. Izzy and friends wonder if she is the reason for the strange behaviour. They wonder why she has returned.
They find out she was fired. They speculate as to why and decide she's a demon who's returned to do bad things. Because why wouldn't she be?