The jazzophone is a comparatively rare sax-shaped double-belled brass instrument, with a trumpet-like mouthpiece. One bell is left open, while the other bell uses a harmon mute with a stem on a trigger.
Speculation is that the first was created in 1920, but other musical experts disagree there is another form of jazzophone. Collector "captain kuzzoo" claims to own such an instrument. No specific details besides a picture are given, but it appears to be a kuzzoo shaped body with a single bell. The previous mentioned jazzophone was created completely separate of the "kuzzoo" model. The only common link is the name.
References
Jazzophone Wikipedia(Text) CC BY-SA