This large rove beetle larva was at my dead-reptile carrion bait station, which had earlier had at least one adult Creophilus maxilosus as a visitor. (Adults eat fly maggots, and I suspect the larvae do as well.) Considering its size and location, and the fact I have never found anything similar away from carrion, I think it is most likely a C. maxilosus larva.

In this image, it has bumped into a carrion beetle larva (Necrophila americana) heading the other way inside my light arena. Here is what the adult looks like: