Small and irregularly shaped heavenly bodies made up of gas, dust, and ice particles are called comets.

Here's why:

* Small and Irregularly Shaped: Comets are much smaller than planets and have a distinct, often irregular shape.

* Gas, Dust, and Ice: Their nucleus, the solid part of the comet, is made of frozen gases (like water, carbon dioxide, and methane) mixed with dust and rock.

* Heavenly Bodies: They are celestial objects that exist in space.

Let me know if you'd like to learn more about comets!