Teselecta

The Tesselecta was a machnie that could travel through time to locate people deemed to have broken the law, and without killing them, 'give them hell'

Much of the technology behind these machines is very advanced. Also known as Justice Department Vehicles, a Tesselecta can adapt itself to resemble anyone whose likeness it has scanned. But more than this, it can transform itself to take on the appearance and functionality of non-living matter, such as clothing or vechiles.

The vehicle is staffed by a crew that have been miniaturised and kept in a Borrower-like state by a compression field and the Tesselecta the Doctor encountered in Berlin, 1938, was Justice Department Vehicle 6018. Deadly, powerful and almost unstoppable, it was only defeated when Amy forced its ruthless crew to abandon it. (DW: Let's Kill Hitler)