Fans who've been waiting patiently for Forge Island to land on Halo 4 were surprised by its early availability, after 343 launched the anticipated map editor at the tail end of last week.
It's a response to fans requesting a flat playing area in which to construct custom maps, and offers three modifiable areas for gamers to let their creative sides run amok.
The early arrival of the content is down to it passing the certification process early. It weighs in at just over 150mb, and is available to download now.