My game started glitching up on a multiplayer server while I was riding my horse so I restarted my game, logged on to the same server, and found myself inside my own head like when there are multiple players on one block. I went into F5 mode and found that there were two players with two identical horses, me and...another me. I could see the other player username which was OceanArrow (it may have said OceanArrow52 but I was too confused to check) I tried messaging the person but it said 'Error: Player not found.' People started asking in chat why my username on Tab was white (there are no white usernames on the server) I started attacking the duplicate player and found it took damage, so I pushed it over the edge of the ravine. The horse died and the player was blown up by creepers but my horse and me didn't die which I found strange. It didn't show up in chat that this 'OceanArrow52' died (the only reason I know it may have been OceanArrow52 was because is said on Tab next to my user, OceanArrow). I know by now you're probably thinking that it was just another player but I'm sure it wasn't because it appeared as soon as I logged on, had exact same skin and horse (saddle and armor included), was standing on same block, didn't talk or respond to messages (even though I couldn't send them), had same armor and weapons and neither horse or player didn't drop anything when died. I apologize that this report is so long and that I am not able to provide a screenshot (can't access screenshot file).