As said by WildcardJen on Reddit:
In just 1 hour, at 12pm EST, ARK will begin it’s final Survival of the Fittest competition for 2015. And we’re going out with a bang! http://www.twitch.tv/survivetheark/
This new competitive Total Conversion Survival of the Fittest mod pits Survivors against each other in a massive ‘100 versus 100’ Two-Tribe war, featuring the likes of your favourite streamers, previous tournament winners and some of the best Survival of the Fittest players who roam the isle. It’ll be a truly special elimination battle, the likes of which has never been seen before on the ARK!
The 100 players on the winning tribe — either Tribe “Naughty” or Tribe “Nice” — will get to divy up $10,000 to donate to which charity they choose from a selection of five wonderful charities: Childs Play, TakeThis, AbleGamers, Charity: Water, and GamingForAdoption. Each of these charities will receive an additional $1,000 on behalf of Studio Wildcard.
Tune into www.twitch.tv/survivetheark today at 12PM EST to watch the epic three-hour event unfold and cheer for your favourite survivors. This winter special will be hosted by your favorite casters, BikeMan & JayEx23!