To unlock this you have to get to the top of the skyscraper/hotel in the map Goat City Bay. Quickest way to do this is walk to the hotel lobby and enter the elevator. However, if you wish to unlock
at the same time, then there's a video below for unlocking both. Recommended mutators: Double Jump (unlocked automatically) and Angel Goat (should unlock by not causing any mayhem for 5 minutes). Credit for the video goes to YouTube user Maxen Thirteen.