The 'Oppenheimer Smile' meme, also known as 'Oppenheimer If He Invented Something Fun,' features a digitally altered or AI-enhanced image of Cillian Murphy’s portrayal of J. Robert Oppenheimer. While the actual film is famously somber and brooding, this meme depicts the physicist with a wide, joyful grin, contrasting his serious historical legacy with lighthearted alternative realities. It first gained traction on platforms like X (formerly Twitter) and Reddit following the release of the 2023 'Oppenheimer' film, often paired with captions suggesting he had invented harmless pop-culture staples like Vine, the Xbox 360, or fast food. It serves as a humorous commentary on the 'Barbenheimer' phenomenon and the sheer intensity of the original character's persona.