Transloc

A  was a very small tracking device that could be placed on a target to monitor their movements. Though there were similar devices in many cultures, a "Transloc" was of specifically Dalek design.

ADF agent Reb Shavron once had a Transloc placed on her person on the Dalek-infested planet Omegon. Android Mark Seven discovered the bug and placed it on a local spider, so as to confuse the Daleks. (DWA: Exterminate! Exterminate! Exterminate!)
 * ''The word is capitalised in the source text.