The Turtle Rock developers while making Evolve added in a special identifier for when they played in-game as the monster. The special Turtle Rock Gold Skin was added specially for members of the development team so they could identify each other and also as a way to feel good about what they'd developed.
This weekend however as thanks to the support the community has given the game so far, Turtle Rock are making that skin available for players to get. It'll be totally free to get and requires only that you play a few rounds of Evolve between Thursday March 5th 9:00pm PT and Sunday March 8th 9:00pm PT, and you'll receive the TRS Gold skins for Goliath, Kraken and Wraith for your account.
The skins won't be received right away they say, but they aim to deliver them sometime after the weekend but before Sunday March 14th.
Turtle Rock also plan to issue challenges and events in future to allow players to earn more rewards in-game, although the only hints we have about any of them is that the next event coming up will be the "St. Patrick’s Day Trapper Challenge".