Judoon scanner

Judoon scanners were used by the Judoon

Appearance
The device itself somewhat resembled a red dumbell-sized sonic screwdriver. When in use a blue light shone from the end and made sounds much like a metal detector. A black marker was on the opposite end, which was used to mark individuals who had been checked.

Abilities
The scanners could be used to identify an individual's species. The scanner could also be used to identify foreign languages as well, so that the Judoon could communicate with any species fluently. The sounds made by the scanner may be how the Judoon interpreted the results, as their ears twitched when a scanner was operating.

Plasmavores could hide their true identity from the scanners by assimilating the blood of a human or other species. Scanners had a higher setting, which would force a Plasmavore to assimilate a second time in order to remain hidden. Also, if a foreign species came into close contact with an individual, such as through kissing, it could leave mild traces that could be picked up by the scanner. This often resulted in a long and tedious process used to properly confirm what species the individual was. (DW: Smith and Jones)