Eva

 is Boris' feline familiar. She changes into a woman to attend Endora's Halloween party at Samantha's and Darrin's house. She flirts shamelessly with Darrin. Later in the evening, Eva performs a special dance called the Pussyfoot. At midnight she changes back into a cat.

Later, after Endora punishes Arthur for his pranks, Eva, Boris and the rest of the guests leave with Endora to continue the party in Venice.