The machine scanned his movements, waiting until its circuitry told it that the optimum moment had been reached. Its programme instructed it to capture without harming. Mark reached the table and stood for a second, looking around like a meerkat. Above his head, the crab-machine's circuitry brought millions of data streams together and decided that the optimum moment was now. It released its grip and fell towards the figure below. Mark ducked under the table to reach for his phone. A crashing sound of something landing on the table shocked his already-heightened awareness, and made him dive fully under the table. There was a skittering noise on the table top, and two thin metallic legs stretched down from one side to reach underneath. On instinct, Mark jumped into a crouch, put his back against the underside of the table-top and pushed upwards with all his strength. The crab-machine flew into the air, crashing through the kitchen window and thudding onto the grass in the back garden. Mark ran to the window to see what it was. He didn't have a clue. Judy might know.

<Judy, what is that?> The machine lifted itself off the ground, glinting in the kitchen light. One of its legs had snapped.

<Describe it.>

<It looks like a shiny insect.>

<Run. Now!>

Mark didn't need any further prompting. Even as he turned to run, the machine began moving towards the house with impossible speed.

<What is it?>

As Mark ran through the kitchen door into the hallway, the machine scaled the wall outside of the house and thrust itself back through the kitchen window. Mark grabbed the kitchen door handle and slammed the door shut behind him. If he was lucky, the machine would be trapped in the kitchen and would not get access to the rest of the house. The machine, thudding against the closed door, shook the walls.

<It's called a Hunter - a Centrid device. Very fast. Very efficient. Very dangerous.>