To promote Sonic World Adventure's launch in North America and Europe, SEGA's website released Sonic: Night of the Werehog as an ONA. The story follows Sonic and Chip as they explore a spooky house on a stormy night. Two mischievous ghosts inhabit the house and aim to frighten guests for a photograph to impress a female ghost. Despite Chip's fear, Sonic remains unfazed by their antics, causing the ghosts to band together to take Sonic down. Can Sonic harness the power of the full moon to overcome their efforts?