Yes, this is about Dr. Evil's dream: Sharks with frickin' lasers. Except that the lasers would not be artificially attached, but be part of the animal itself (bio-lasing instead of simply bioluminescence).
In short: Would it be possible for an animal (shark or otherwise) to grow a laser at its head and put it to use? This could be a genetically engineered animal, but the laser is supposed to grow, not to be artificially attached, and the animal is supposed to be able to use it "naturally" (that is, without needing special training, similar to how it uses e.g. its voice or its muscles), either for catching/killing prey, or for fighting predators or other animals which pose a danger, or maybe even simply for signalling (similar to a laser pointer).