|"That's not what happened at all!"
This article is about something not canon to either the storyline of the TV show or The LEGO Movie franchise.
Mystery Dust was a living dust pile that resided in Steeper Wisdom.
Cole tries to sweep the dust off the floor and fails miserably. He places the scoop on it, which it consumes before Cole does Spinjitzu, throwing chairs at it, which it consumes and grows. Eventually, Cole uses a vacuum cleaner to suck it up. It caused the vacuum cleaner to clog up due to its mass and causes the vacuum cleaner to explode, spreading the dust everywhere and releasing everything it consumed.
- 11. "Mystery Dust" (non-canon)