There is no clear answer to what happened to Damar Hamlin on Reddit, as the search results show a mix of posts discussing his collapse during an NFL game, his medical condition, and his potential return to playing football. However, some of the posts suggest that he collapsed due to commotio cordis, a rare but potentially fatal condition that occurs when a blow to the chest causes an abnormal heart rhythm. Damar Hamlin was discharged from the hospital nine days after his collapse, and according to a post by Capaccio on Reddit, he is preparing to play this season and has been cleared by all specialists to resume full activities.