Summer Slack is a music video for the ZUTOMAYO song of the same name, directed by Rina Mitsuzumi. The track first played as an insert song in the anime film Drifting Home. The video puts Nira-chan, the character familiar from ZUTOMAYO's music videos, into the world of that film, and most of its footage consists of scenes that do not appear in the movie itself. It is a single-episode music release with a supernatural flavor.