Anniversaries/October 21
From Sonic Retro
October 21 (add)
- 1998 — Issue #141 of Sonic the Comic is released in the United Kingdom.
- 2009 — Issue #9 of Sonic Universe
- 2015 — Issue #277 of the Sonic the Hedgehog comic series by Archie Comics is released in North America.
- 2017 — "Don't Make Me Angry", the 100th episode of Sonic Boom, airs in North America.
- 2020 — Sonic the Hedgehog, a Blu-Ray, is released in Japan.