Pictured above right is anearwig for comparison
When alarmed they will curl the tip of their abdomen up and over their back and move erratically to escape potential threats. They move rapidly and are often very difficult to photograph and this one was no exception. It took quite awhile to manage a couple of decent images before I finally gave up and it disappeared underneath another rock.
As larvae and adults they use their strong pincher-like mandibles to feed on other insects especially fly larva, and should be considered beneficial to humans for the pest control they provide. They are also one of the insects collected at crime scenes to aid in determining the time of death of a corpse as they are attracted to carrion and will feed on the fly larva also attracted to rotting flesh. One could say they are opportunistic hunters.