Christmas Frostivus in Dota-land, but Rubick doesn't care. "Swept up in the zeal of unraveling and reshaping arcane energies" - we've all been there - "Grand Magus Rubick marches a mob into Frosthaven, intent on uprooting the original Frostivus tree to explore the mysterious font of power beneath it." Which means, of course, that five heroes have to defend a Christmas tree in co-op wave survival.
I've had a go! It's better than usual. Mostly because of the bonus round where you get to ride penguins.
Here's the Frosthaven update page.
As per Dota holiday event tradition, the attackers are a mix of new creatures and familiar heroes. They spawn in at the edge of the map each round, which usually sees everyone splitting up at first then grouping up again as the outer perimeter of towers fall. All the buildings respawn if you survive, though you earn bonus gold if you keep them standing.
I see it less as an interesting tactical challenge and more as a showcase of festive Dota weirdness. The first wave dresses up creeps as pinecones, and later on there are grumpy ogre seals wearing antlers and Rudolph noses. I'm very glad those didn't wipe my group out, because the next round turned out to be a bonus gold-collecting one where everyone had to steer penguins with terrible handling into snowmen and a gingerbread Roshan.
Though he doesn't deserve it, Rubick has also been given a Christmas present. It's one of those Arcanas that bundles together a bunch of dramatic cosmetic changes, including green-tinged Rubickified versions of 115 stolen spells. They do look snazzy - I particularly like the cube he calls down instead of Invoker's chaos meteor.
It also gives him a cape that changes colour depending on which spell he's stolen though, which looks neat but communicates information that is normally slightly hidden and if you wear it you are silly. Not just because it costs £28.