The 'Marine Todd' meme is based on a viral copypasta that circulated through chain emails and Facebook posts in the early 2010s. The story typically follows an arrogant atheist professor who challenges God to stop a piece of chalk from breaking, only to be physically confronted by a brave US Marine who had just returned from duty. While originally shared sincerely in conservative and religious circles, the story became a subject of heavy irony and parody on platforms like Reddit and 4chan. Users often remix the story with absurd endings or replace the characters to mock the 'r/thatHappened' nature of the original story, making it a staple of internet culture satire.