He would normally have 6 legs. He now has 5. Two of them are pointing forward and look like antennae. One of the websites I looked at said there are something like 3000 species of walking insects in the world.
We find them often on screen doors in the evening. The later in the year, the bigger they get, the easier they are to find. Kind of funny how they walk. Kind of rock forward a few times then take a step, then repeat.