Optical correlations represent a resource for the development of technologies with very promising opportunities for future widespread applications.1–14 Here we will show, both theoretically and experimentally, the optical illusionist game, an innovative protocol that exploit correlations between thermal beams of light.15 In the game, an illusionist demonstrates that if two uncorrelated light beams excited in the same state are mixed in a beam splitter (BS), then no correlations arise between them. On the other hand, the presence of the BS can be identified by the illusionist when the public is asked to insert the BS behind the illusionist’s back. Here we unveil the trick and the physics that explain these counterintuitive correlations. 1