Razor backed land shark

A creature which was genetically mutated after the nuclear war and became perfected adapted to its environment. The pines on its back make it look at one with its environment and makes this beast almost invisible to the naked eye. Not only this but its huge amount of power and speed make it pretty much unstoppable. Any creature or person knows to fear the land shark, though very few ever get the change to tell stories of encountering one because their usually one of the last things people ever see.