The Game Awards started off its pre-show with a quick peek at the newest content coming out for Goat Simulator. The trailer featured quite a few animals besides the titular goat talking about the nature of DLC itself and why indie developers make it. There weren't many jokes in there, which was most likely the joke itself.
In any case, this "Super Secret DLC" seems to feature quite a few new playable animals, including a dolphin and a flamingo, as well as at least one new setting to tour around while you lick, headbutt, and otherwise wreak havoc all around the town.
There was no announced release date or even a final name for the new content, but considering the nature of the game, you can most likely expect it sooner rather than later.