Horror film made in the 70's or 80's about a wax museum?

I saw a film when I was younger about a bunch of kids sneak into a wax museum and when they step into the display of wax vampires they kinda step into a world where the vampires come real (if ya get me at all). I remember one scene where one of the kids was tied down on a slab and one of the vampires was just picking away at his leg eating it. Thats all I remember, and it looked like it was made in the 70's or 80's I was just wondering the name of it if anyone saw it.