Finally, finally I know what these insufferable multi-legged dealies are that run along my wall: house centipedes. According to Wikipedia, these 30-legged devils will sometimes bite humans with the pain- equivalent of a bee sting. This, in my opinion, is a sufficient explanation for the three welts I woke up with last month.
Anyway, I found another one running along my wall when I came back from dinner, so there's now a plastic cup taped to my wall with an unpleasant monster trapped inside. When he dies I expect to take a photo.
Me : "I just wish I knew what these things are!"
Aaron : "I want to have a look at that thing; I might be able to identify it. You know. Because I know my way around an invertebrate."