For one of season 6's episode, the Adventure Time crew handed off an entire episode to anime director Masaaki Yuasa, who helmed his own episode without any creative input from the normal creative team. The results are insane, which, for AT, is saying something.
Yuasa, who is currently directing the Ping Pong anime, wrote, storyboarded and directed the episode titled "Food Chain" by himself, and here's a three-minute preview. According to Vulture, the episode will not be considered canon, although at the moment it seems to fit in with Adventure Time's regular episodes reasonably well, just... with the bonkers turned up to 11.
The episode will debut in June, but remember, season six of AT premieres tonight on Cartoon Network.