The Navy just recently deployed their first operational laser cannon, and surprisingly it wasn't mounted to a shark!
The Navy's Laser Weapon System (LaWS) is perched atop the bridge of the USS Ponce, an Afloat Forward Staging Base (AFSB) ship. The AFSB concept provides a floating staging area for various amphibious operations, and the Ponce is currently providing for humanitarian and military operations in the Persian Gulf.
The LaWS is a 30 kilowatt laser, primarily designed to disable unmanned or light aircraft or smaller boats that come too close to the ship. The development cost for this weapon were around $40 million over almost 10 years, but unlike other kinetic close-in weapons systems (CIWS) such as the Phalanx or the Rolling-Airframe Missile, each shot costs less than a dollar!
Development has begun on a larger, 100 kilowatt laser that would be more powerful and more effective against larger targets.
The Navy has also just released video of the laser in action: