A Zorg is a hostile creature in the Spaceman Spiff universe that comes in different shapes and sizes.
A giant Zorg is encountered by Spaceman Spiff in a Sunday strip. In it, Spaceman Spiff is chased by a Zorg (Calvin's Mom) and when the zorg grabs him, he tried to use his blaster, only to find out that the it is useless (as his weapons often prove to be). The Zorg then takes Spaceman Spiff to its cave (Calvin's bathroom) and tries to cook him alive in a vat of boiling water (the bath). The strip ends with Calvin next to the bath, and his mom saying : "Well? get in" with Calvin responding, "Don't you want to lean way, way over, and test how hot the water is?"
A smaller Zorg was once encountered by Spaceman Spiff in an early strip (with the Zorg being a counterpart of Principal Spittle).