Skovox Blitzer

A Skovox Blitzer was an alien robot built for war, said to be among the most dangerous weapons ever created. A single Blitzer carried sufficient explosive power to destroy an entire planet.

Characteristics
The robot's physical form was composed of a humanoid torso with stocky arms on top of a larger box-like structure, with four crustacean-like legs in the corners that propelled the robot when on the ground to roughly the same speed as a running human. According to the Twelfth Doctor, the Blitzer could fly, as well as travel across space, hinting that it had homed in on the target area on Earth without external help. This would also account for its strange, floating method of movement when on the ground, with the legs being responsible for propulsion without being slowed down by supporting the body's weight. Its weapons were built into the arms, with the right arm possessing a triple-barrelled rapid-fire weapon which could shoot three simultaneous green energy bolts that caused its target to rapidly burn and disintegrate, and the left arm housing a single-barrelled energy weapon that fired white energy bolts that could explosively vaporise anything within its range.

Unusually, Skovox Blitzers were designed to vocally state aloud whatever they were mentally processing, from environmental information that they had scanned, to whatever instruction they were currently following. They were also programmed to think that the answer for almost every problem was to destroy the source/obstruction and apparently had been designed to not differentiate between enemy combatants and unarmed civilians, despite any claims from the target of being friendly and harmless. If ordered to shut down without the necessary final input code, they would self-destruct and destroy the planet that they were on. (TV: The Caretaker)

History
A Skovox Blitzer came to Earth in the early 21st century, attracted to the area around Coal Hill School by the high number of artron energy emissions. Whilst there, it killed Matthew, a local police officer. The Twelfth Doctor detected the Blitzer and trapped it in Coal Hill's school hall and projected it into the Time Vortex using chronodyne generators. However, Danny Pink had inadvertently interfered with the generators and the Blitzer was not projected as far into the future as the Doctor had planned, reappearing just two days later rather than a billion years. Before it reappeared, the Doctor developed a device that would make his orders sound as though they were coming from one of the robot's superiors. With the assistance of Clara Oswald and Danny, he again trapped it, and ordered it to deactivate. He then left it to self-destruct in space near the Olveron Cluster, telling it to "enjoy [its] war". (TV: The Caretaker)

Behind the scenes
The Skovox Blitzer was played by Jimmy Vee.