The horny one
Brass instruments create sound through air vibrations in a tubular resonator. Common brass instruments include the trumpet, french horn, trombone, euphonium, and tuba.
Whatever they could fit in a trunk and thats it..
A couple of things could fit that description. Cornet, flugelhorn, French horn all come to mind. A cornet and flugel horn play exactly like a trumpet. A French horn is is normally in a different key than a trumpet.
relay, probably under the instrument panel
It could fit, but it will be loose.
Yes. Most people with cars today are thinking of changing their current horn to a truck horn by simply putting the horn at the back part of their car.
A dragon does not fit because it does not have a horn.
PUT IT IN YOUR BACK SEAT.
A sousaphone is portable. It's bell can be removed by loosening three screws that fasten it to the rest of the horn. The rest of the tubing can then fit around the bell and the entire horn can fit into a small, but heavy case.
There are two main classifications of percussion instruments. Idiophones include things such as cymbols and maracas. Membranophones include common instruments such as drums.
I would suggest that you start at your local musical instruments dealer.
Drums - are part of the percussion group of instruments.