A weird glitch in my game.

So, recently I had a glitch that happened in my world. It was to say the least, pretty weird and creepy. Like one of those old Minecraft videos with Herobrine and stuff. But the thing is, unlike those videos, they were staged, I mean it's evident now that we aren't kids anymore. But my world is on singleplayer, and things such as footsteps and items disappearing is something that wouldn't happen. But my game was already glitchy as it had a bunch of texture glitches in the newer versions that displayed it ass old. Can anyone be able to explain?