[6] The illustrated novel is based on a character Sun developed on Twitter,[7] tweeting as an alien trying to learn to navigate life among humans.

[8][9][10][11] He has said the period in which he was beginning graduate school (and the toll that took on his mental health) was the impetus for the project, with the character offering an opportunity to work through the isolation and depression he experienced.

[7] Sun's second book, a collaboration with musical playwright and actor Lin-Manuel Miranda, was released in October 2018.

Little Pep Talks For Me & You, is a collection of affirmations drawn from Miranda's Twitter feed and illustrated by Sun.

The book was written during a self-imposed break from all of his work and it became an instant New York Times bestseller, receiving praise from critics who remarked on Sun's "personal voice" and "little bits of ephemera.