Pistol Shrimp

Bought this critter a few months ago. At first, I thought it was a Debelius Reef Lobster, but it had an orange body with just a pair of large striking purple dots. The claws were also purple, one side being larger than the other. At that point of time, I couldn't identify this crustacean.

Lately it had been making some interesting snapping sounds. I feared that a Mantis Shrimp was in my tank. But recently went thru www.liveaquaria.com and found that my "lobster" was actually a Pistol Shrimp