Teslas make there home in cool areas. This is because, when in heat, the Tesla's vitae will splinter, causing it to become further unhinged from reality, until it eventually becomes truly invisible to the naked eye. The Failed Experiments located in the sewers underneath Oswald Mandus' home are the end result of this transformation.
The Tesla is a monstrously large mutated pig that can move both quadrupedal and bipedal, similarly to Engineers. It also has many electrical devices across it's body, making it easy to locate in dark areas. Though it, like the Engineer, is a substitute for the Brute, the majority of its physical traits mark it as an overgrown Wretch.