The Great Spirit Puck's Nyan Nyan Sunny Day (大精霊パックのにゃんにゃん日和) is a shop exclusive limited edition short story. This was later adapted and included in the Re:Zero Ootsuka Shinichirou Art Works Re:BOX.
Subaru, being incredibly curious, asks Emilia about what does Puck do whenever he is not around her, she says innocently that Puck must be always doing incredible deeds each day like saving the world or helping those in need but also says she is not exactly sure. Subaru being determined to find the truth about Puck convinces Emilia to tail Puck for a day and they discover his activities are pretty much those done by a normal cat. At first Emilia was in denial of this fact but soon accepts, gets disapointed and angry at Puck for telling her that he always does very important stuff in his alone time.