ok this one is a lil hard to describe but i will do my best.back in 1995ish era i went to a haunted house that used metal floor sections as a startle prop.you could not tell the diff between this and the real floor unless you looked real hard.so anyway as you walk through the haunt you step on the panel and it would make a loud sound and the floor would vibrate.is this a homemade prop?anyone know what im taking about?

btw no sitting on the vibrating floor jim