Teselecta antibody

The Teselecta Antibodies were robotic guards inside the Teselecta. The antibodies served as security, killing anybody who did not have the correct privilege to be in their sector of the Teselecta. A Nazi general was one such victim of the Teselecta Antibodies. They often yelled things that a doctor or an executioner would say combined, such as "You will feel a slight tingling sensation...and then death."

When Amy and Rory turned off the Teselecta's automatic staff notifier (their wrist device), they all teleported away, leaving Amy and Rory to be killed by the Antibodies.

Appearance
They were about four feet tall (miniturisation ray notwithstanding), with bulbous heads. Cables, resembling tentacles, protruded from this head, giving it the appearance of a cephalopod. (DW: Let's Kill Hitler)

Technology
They had anti-gravity technology and hovered through the air. They used a laser to kill their targets, and could also manipulate their wires to hold people in place.

The antibodies could only recognise if a person had the correct privileges by noting if they had a bracelet that glowed green. Without that device, they would politely incinerate the intruder.

They emerged from consoles in the Teselecta's main robot. There were at least a dozen of them. They also had access to scanner technology, as they could tell that there were only two humans on board the Teselecta after the crew had beamed off. (DW: Let's Kill Hitler)