Vault 8166 rumor

 Vault 8166 is rumored to be a hidden server on Roblox where un-explainable things beyond usual are occurring. It is allegedly a secret map ran by unknown hackers, which have the ability to watch or monitor activity going on between users. It doesn't appear to be a literal vault itself, but it's believed to be a metaphor meaning

"Vault/containment of hackers", It is said that anyone who goes there can gain access to certain information on Roblox and use the Installations, GUIs, and programs. It is then used to create new software, bots, or viruses that are placed and hidden into Roblox models or plugins. When inserted into a place, they obtain the ability to interfere with gameplay, local scripts, and even computer monitors. Vault 8166 is described as "the reason behind the Roblox website 's sudden maintenance,'' but nobody is completely sure.

The First Mention of Vault 8166.
On November 15, 2016, an anonymous user created a new thread on the Roblox Talk sub-forum. This user was claiming to had accidentally gotten into this "unknown place" while testing out a teleporter for a game. The thread was a brief summary of how "evil is operating behind our eyes", and that there is a place where dangerous people are gaining access to user profiles and other information as we speak. This secret place was referred to as  "Vault 8166" . A few hours after the thread was posted, word went out. Mysteriously, the thread was nowhere to be found, along with the user who posted it. The thread may have been taken off by moderators. If not, something else was at work, and it wanted it gone.

People have thought that this forum post was the final message sent by one of the users in the footage above before they got captured after one of the users found out that the footage was taken 2 minutes after the forum post was posted, this was proven by using the Wayback Machine.

Two Users Attacked by an Unknown Figure
Recently, a user-submitted footage of what seems to be a hallway of Vault 8166. The time and date this was recorded are taken on November 15, 2016, the very same date as the forum post. It starts out with a hallway full of computers with switching screens that resemble codes. It also contains red flashing lights, a strange white room at the end, and a poster containing a skeleton saying "Warning, we are watching you".

Two Robloxians, both of which resemble a common exploiter avatar, walk into the middle of the hallway. One of them is fully the color black, has a particle emitter and red fire. The other is just colored red on the head, and black on the torso. Neither of the nametags are visible. They stop and take a look around, and out of nowhere a strange skinny figure with large legs comes out from behind and starts running at them while waving its arms. Both characters start panicking. Right when the figure reached them, the video suddenly blacks out. While the figure in the video can't be easily identified, we can see that its face was blurred out.