The mode, entitled Rainbow is Magic, appears to be live now, and is set to run for roughly seven days. A description, which you can see in the video from Rainbow Six Siege YouTuber CoreRoss, says that the mode will let players “play special Hostage matches in a dreamy, cutesie version of Plane.”
The idea behind the mode is that everything has been shrunk down. The plane itself is a garish pink model, surrounded by toy cars. The map’s skybox has also been changed, and now rather than being open air, appears to be a child’s bedroom, and even the operators themselves aren’t immune to the changes – previous leaks suggest attackers have received a set of toy soldier-themed skins, while defenders are kitted out in sparkly pink unicorn skins of their own.