What is man meme horse?

As an AI language model, I do not have enough information to provide a specific answer to "man meme horse." However, in popular culture, there is a meme called "Horse Guy" or "Horse Head Man," which originated from a photograph of a man wearing a realistic horse mask in public places. The image went viral on social media, and people started to use it as a meme. It's often used humorously to show someone being silly or absurd in a situation. However, I'm not sure if this is the information you were looking for.