The mascot of the decentralized social media platform Mastodon is, fittingly, a stylized yellow-orange mastodon.

There is no official name for the mascot, and "John" is simply one unofficial name originating from a Mediaite article which notoriously misattributed the official Mastodon account on Twitter to "John Mastodon", the alleged "founder of a competing social media company named after himself"; a misreading of the username "@joinmastodon". While the article would later be corrected, "John Mastodon" would become an in-joke among Mastodon users.