5VE37

I decided its time to stop playing Creative Mode and made a new game in Survival. I've been playing for a few weeks without a sight of something unnatural.
One time,I went to explore on my horse,then I saw a woodland mansion.
I thought,"Wow,a mansion"
I grabbed my diamond sword and placed my horse on a wood fence.
I went in the mansion and in the chat,there was this player in my singleplayer server.
<5VE37> Why are you here?
I was surprised another person was here.
<Blackhole888> ???
<5VE37> Your are not supposed to be here.
<Blackhole888> Wat????
I saw the player,he had a Steve skin.
<5VE37> Leave!
<5VE37> Or i'll...
<Blackhole888> Well get out of my server!
I tried to hit him but it had no effect.
<5VE37> 298393Leave293820
<Blackhole888> NO
<5VE37> Goodbye!
The game crashed.I checked if the world was there,but it was glitched and was titled: Don't Come Back.
That's when I didn't play Minecraft survival anymore.I continued to play my Creative worlds,they worked fine.
I switched the characters in "5VE37" and it sounded like "573VE" Which was like "Steve" but with numbers.
Who was this "573VE"?How did he get in my world?How did he crash the game?
ru:5VE37
Category:Creepypasta
Category:Entities
Category:Supernatural
Category:Short Pastas