You are looking at an original part for the Lionel 6-16752 Marvin the Martian 6655 series Missile Launching flatcar. This is the EARTH DISINTEGRATOR missile that you launch off of that fun modern era car.
Of course, you can use this with ANY missile launching car Lionel has made. Buy it, and make ANY of those cars into a Looney Toons fun car! Or perhaps you want an extra so you can fire more than one at the cat. Your call.