Every Sunday or Monday night, two students — known only as Dangerdust — sneak into a random, empty classroom and vandalize it…with inspirational art!

While their names are unknown, they have been identified as two seniors at Columbus College of Art who are majoring in Advertising and Graphic Design.

And get this — each work of art could take up to 11 hours to complete!!

(Follow their antics on Twitter: @ddccad)

[via Viral Nova]