Globular horns are a very uncommon instrument.
Technically, they are a family of buzzed-lip aerophones, related to trumpets and horns in the same way that ocarinas, or globular flutes, are related to tubular flutes. However, although a technical rationale and category exists for them, I have not yet encountered any other instruments of this form. The globular horns I have built are low pitched, and can be played in a manner similar to a didjeridu. Finger holes can be added to change the pitch. I have built a few globular horns like the second example above that incorporate a goatskin membrane which increases their resonance through sympathetic vibrations, and also permits them to be played as a drum at the same time as they are being blown into.