I think the only thing mentioned so far that we can rule out is Dalek, and that's only because we wouldn't have survived long enough to take a photo if it was indeed a Dalek. Apparently its the only one in the immediate area, stable owner isn't creepy from what I know. There is a powery-boxy-thing in the same room (tack room) so maybe it's a temp sensor to make sure the powery-boxey-thing hasn't gone up in flames?