Rick Morty Dota 2 Announcers
Adult Swim's Rick and Morty and Valve's Dota 2.Adult Swim / Valve

In a unexpected but brilliant bit of cross-promotion, Adult Swim cartoon stars Rick and Morty have leant their voices to Dota 2 as part of a new commentary pack now available for Valve's enormous multiplayer online battle arena (Moba) game. Rick and Morty is a popular series which focuses on the interdimensional exploits of Rick, an alcoholic scientist and sociopath, and his meek grandson Morty. They share a Back To The Future-style Doc Brown and Marty McFly relationship, but what they get up to is far more messed up.

The commentary pack can be bought through the Dota 2 store for £5.33 ($7.99 USD). You can hear a sample of Rick and Morty's Dota 2 commentary in the video embedded below...

Series creator Justin Roiland (who voices both Rick and Morty) is clearly a big video game fan. In the latest episode of season two there's a gag about Rick's tendency to get over-excited about things like Limited Edition Zelda Nintenod 3DS consoles – a joke paid off with Roiland asking to camera that Nintendo send him free stuff.

At the top of the story I called this cross-promotion, but it's not like Dota 2 needs it. The free-to-play game is monstrously successful particularly due to its eSports community, which was recently enthralled by the annual International world championships. The International 2015 had a prize pool of $18m – the largest ever for competitive gaming.

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