From Sonic Retro
December 22 (
- 2005 — Shadow the Hedgehog is released for the PlayStation 2 in South Korea.
- 2010 — Vivid Sound x Hybrid Colors: Sonic Colors Original Soundtrack, an album, is released on CD in Japan. Issue #220 of the Sonic the Hedgehog comic series by Archie Comics is released in North America.
- 2021 — Issue #47 of the Sonic the Hedgehog comic series by IDW Publishing is released in North America.