If you get a kick out of arousing things like peoples suspicions, or your just a shady character who is into all things suspicious, than you should get down with the 'Suspicious Device'.
Suspiciously, the only thing the 'Suspicious Device' does is look suspicious. Simply the outer casing with the easy-to-carry-handle looks suspicious, but the sketchiness is increased with a switch that activates an LED display with suspicious looking red digits. A motor is also activated when you flip the stick, this causes a quietly-alarmingly suspicious whir/hum inside the device.
You could get into some serious trouble acting like a weirdo with this. Make people feel uncomfortable in other ways, Please just don't do it. For blasts sakes it looks like a bomb!