Complex sentence: Mindy is the evil rich and spoiled queen bee of the school attended by all of the child characters featured in the program, who shares a rivalry with Mandy, whom she looks down upon and considers to be unattractive and inferior in comparison with her.
Split into simpler sentences: Mindy is the evil, rich and spoiled queen bee of the school attended by all of the child characters featured in the program. Mindy shares a rivalry with Mandy, whom she looks down upon and considers to be unattractive and inferior in comparison with her.