Out near the Oregon coast as I was working on photographing steelhead, I ran into this little fellow. Quick and fierce looking, and with a red warning color as a bonus, I wasn't sure how well it would tolerate me trying to grab a few shots.
Not too well really. It didn't like the light, and especially didn't like to be out on the rocks since it seemed to prefer a subterranean existence.
I did manage to coax back into a spot where I could get a clear image, and it helpfully paused to groom its antenna. Even so, I had seconds to grab these before it disappeared again.
legs of a red centipede (Scolopendra polymorpha)