This is my Monster In a Box prop.  This prop was built for my 2005 haunt and it is driven by a drill.  The drill in mounted in a 2x4 frame that has a cam mounted to the drill chuck.  The cam rotates and moves a push rod that opens and closes the lid very fast making several loud bangs.  We also mounted red lights and a small tape player inside to make the prop look and sound more menicing.  We used a manual switch to run the tape player that has growling and roaring noises on it.  The red lights are on all the time and look like red eyes in the box.  We ask the TOT if they would like to see my Monster we keep in the Box and curiosity takes over.  They step closer and closer and when they are about a foot away from looking into the bars we trip the prop.  I have gotten everyone that looks in the box so far.  Some have jumped about a foot in the air when the prop is tripped.  I also get alot of chuckels from the parents that wait out on the side walk.  This is a very fun prop to have.  I wish we would have set up a camera to film the reactions we got from this prop.