Building "movie-like" Chainsaw Cabinet is really quite simple. All
you need you can find at any hobby shop and your local hardware store.
Enough wood (or other apropriate material) to construct a sturdy 1/2 wall between your guests and the scene.
An old metal cabinet or locker big enough for your actor to fit through.
A sound system of some kind.
A strobe light.
A power strip with an on/off switch.
Low-watt red light bulbs and appropriate fixures.
Audio tape of continuous chainsaw sound effect.
Light weight chainsaw with no chain.
Construct a sturdy, waist-high partition, leaving a narrow path for your guests and a semi-large area for the chainsaw room.
Take the back off the metal cabinet, securing it to a wall with a hole in it or to the ground. If your cabinet is not against a wall you will need to block off the area around it so your actor has a large enough hiding spot where your guests cannot see him.
Hook up your sound system, plugging it in to the power strip. Strategically place your speakers (I suggest hiding them in crates or in the bushes). Keep the audio tape on play.
Position the strobe light behind the 1/2 wall, pointed up at the general area of the cabinet. Plug it in to the power strip and keep it in the "on" position. The strobe works best on full speed for this effect
Decorate the area acordingly (we used mutilated bodies, you may want to tone this down) and light it with dim red light, keeping light primarily off the cabinet.
When your guests walk past, looking at the scene, your actor, chainsaw in hand, spies them through the cabinet (left less than an inch ajar), turns on the power strip and barrels through the cabinet, towards your guests. A sure-fire scare!
I used this effect as part of a walk-through haunted house attraction but it stands on
it's own fairly well and if you're aiming to scare your guests this gag almost never fails.
The chainsaw theme is a little intense for Disney standards but you can tweak the gag in order to
fit your theme. You should keep in mind that this effect requires a human actor.