Who started “Slender Man”?

Eric Knudsen ('Victor Surge'), on Open web, Jun 10, 2009. It reached 7 platforms in 10.0 years.

LineageEach dot, 1,000 slender Man sketches on DeviantArt, WIRED's reported lower boundContestedKey steps, 12 of 16. Lines follow time and platform
GerogerigegegeBefore the first postEric Knudsen ('Victor Surge')First postVictor SurgeOpen webPlatform jumpPressPressMilestonePlatform jumpCommercialBacklashAfterlifePlatform jumpPatient zero