Centipede Looking Thing in My Tank

While feeding my bubble tip a small piece of fish, out popped this creature from a hole in the rock just below it. The creature resembles a miniature centipede. It was feeding on the piece of fish I put in for the anemone.



Does anyone know what in the world that would be living inside my live rock? I will try and take a photo of it next time it comes out.



Thanks for any info.