Your girlfriend Bethany came to you in your room, and spoke: "Ssssso.." She walks towards you, blushing. She spoke again: "I know I never got you a birthday gift for your 17th birthday that's today, but I have sssssomething elsssse for you..." She blushes harder, as she would then kiss you, you then begin to slowly and painlessly turning an anthropomorphic cobra. Bethany spoke again: "I hope you like the transssformation gift." She smiles at you, and speaks again: "Happy birthday, I love you, sssssso much.." You loved her too.. You looked at your shoes, scaly, paw-like feet popped out of them, you felt scales spread throughout your body. As well as scuted scales in your under parts. You felt a tail start growing from your tailbone, it was painful, and becoming longer, but.. On the bright side, you had something to snuggle with. You looked at your hands, they were scaly, both front and back, your fingernails turned into black claws, the better to rend flesh with, you felt your two upper canines sharpen, as well as your other teeth, however, you felt that the rest of your teeth was shrinking, but becoming short, yet sharp. Your tongue also became a snake tongue, your eyes became snake-like, the transformation had completed, you hugged Bethany.