Swordfight On The Frights

How I wish I recorded this... One day I was playing swordfight on the heights (the newer one). I played for a few hours since it's immersive I guess. I was just killing other players until I noticed this thing... It looked like a player but wasn't a player. It had no humanoid, I know this because it had studs on its shoulders which usually happens when some sort of character has no humanoid value. It managed to navigate the map somehow? Jumping across the platforms that went invisible after some time, it managed to make its way to the middle where I was. I tried to kill it with my sword out of curiosity and nothing happened. Surely in a game with filtering enabled infinite health scripts wouldn't work at all? The thing couldn't be an exploiter... After proceeding to try and kill the thing, it just stood there. After about 5 seconds it sunk into the ground never to be seen again... I said in the chat "Did any of you guys see that?" and I never got a response... I am able to recreate what it looked like so I'll show you the screenshot.