Cassandra is a witch and appears in the episodes Halloween Show and Tabitha's Party of Tabitha.  She sent a hit witch after Paul to make his life miserable because of what he said about witches on TV. When Aunt Minerva told Tabitha about her plans, she put a spell on her taste buds.  In "Tabitha's Show" she created a love potion that works on witches.  Aunt Minerva also mentioned that she is on the Witches Council.