 " Walnuts & Rain " marked the first time that Herpich had solo @-@ storyboarded an episode since the third season episode " Thank You " . The episode was seen by 1 @.@ 68 million viewers , and received mixed reviews from critics ; while Andrew Tran of Overmental enjoyed the allegories in the episode , Oliver Sava of The A.V. Club somewhat critically compared " Walnuts & Rain " to episodes from the show 's first and second seasons . For his work on the episode , Herpich won a Primetime Emmy Award for Outstanding Individual Achievement in Animation ; this was the series 's third win in the category . For his work on this episode , Herpich was later nominated for an Annie Award for Outstanding Achievement , Storyboarding in an Animated TV / Broadcast Production in 2016 . 
