Minecraft Alpha 1.0.16 Versions, or AlphaVer, is, quite literally, an Alternate Reality Game. The videos start out as Herobrine creepypasta found footage, but as it progresses you see the development of this Minecraft version into something completely unrecognizable from the vanilla game...

There's 2 videos on it by RetroGamingNow that describe the ARG in detail, but I'd like to share my favorite video from it:

oh yeah you can also download and play the versions yourself. So much effort has been put into this ARG it's insane