Introduction 1: Snape, who originally died in the Shrieking Shack, became a fifteen-year-old boy with cat ears. The only way to keep him in human form is for Harry to give him a true love's kiss every day! If you want to return to your true human form, you have to fall in love with Harry and make love!
Introduction 2: As we all know, Harry Potter's cat is the worst-tempered cat in the UK and most resembles his former professor. Harry himself couldn't argue with that, especially when it slapped his teacup over with its paw and said "you troll" with its eyes.
Intention: The cat-eared man is here!