'Twas the night before Christmas

And all through West Philly

A creep was on the prowl

And ended up shocked silly

A knife-wielding scumbag attempted to sexually assault a woman last night as she was walking down Graham Street near Vine in West Philly, police said.

Just before 8 p.m., the victim, 19, was walking home from SEPTA's Callowhill Depot, at 58th and Callowhill Streets, when she noticed "a shadow coming from behind her," police said.

That shadow belonged to a man, who pulled out a knife and held it to her neck as he dragged her toward a darkened alley. When the attacker tried to have his way with the teen, she zapped him with a stun gun and sent him running, police said.

The woman was not injured in the ordeal.

Police describe the suspect as a man in his late teens or early 20s, who wore a gray hoodie, blue jeans and green and blue sneakers during the incident.

Tipsters can call 215-686-8477.