Sometimes also called a Pillar Dial or a Shepard Dial

This strange looking device is actually a portal sundial! The metal arm is the “gnomon” (the part of the sundial that casts a shadow) and the body is carved with different curved horizontal lines for times and vertical columns for months

This sundial is set for the 37th parallel north (37.3 degrees North latitude) which includes places like the island of Sicily, Greece, as well as places in Syria, Iran, China, and through the center of the United States. This kind of information can make it possible to determine where this device was originally made or at least where it was intended to be used 🔎

Helpfully, it also just so happens it is “inscribed on the dial corresponds with that of Catania in Sicily” so this device was likely made to operate in Sicily

(A very simple) Mystery solved!