Girl Ignores Monster Warning!

by Ben
(UK)

I saw a horror movie when I was a kid in the late 80s. All I remember is a scene where a girl is being chased down an alley or street by some kind of monster/zombie. I think the monster had several heads or faces merged into its body. The girl runs into another girl that is sitting on a wall and tells her to run. The other girls ignores her, and the monster comes from around a corner and attacks her.

I have been looking for this for years - any ideas?