http://www.pcgamer.com/arks-next-expansion-will-contain-underground-biomes-and-chest-bursting-critters/

Ark: Survival Evolved, in addition to launching from Early Access this week, announced a $45 season pass, which includes the Scorched Earth DLC as well as two unannounced expansions. We've now learned a bit about one of those expansions, called Aberration, which is set to arrive in October of this year.

The Ark (planet) in Aberration isn't quite as friendly to organic lifeforms as the one we're used to. The atmosphere has bled from the Ark and the sun is highly radioactive, meaning if you're going to thrive and survive it'll have to be underground in caves (at least until you've crafted some protective gear, we assume). Those caves, at least, look pretty.