Evil Instinct (1996)

Name: Evil Instinct
Genre: Mystery, Thriller
Released: 1996-05-04
Duration: 95 min
Cast: Carrie Ng Ka-Lai, Diana Pang Dan, Bowie Lam Bo-Yee, Evergreen Mak Cheung-Ching, Stuart Yung Sai-Kit

Penny and Wendy originally are co-workers and best friends until Wendy is promoted. Penny feels that she is getting old and can't compete with Wendy, she leaves Hong Kong, takes snake blood to cleanse herself, and then returns to Hong Kong for revenge.