SCP-012 is an SCP whose containment cell appears in SCP: Secret Laboratory in the Light Containment Zone.
Official SCP Wiki Information
"SCP-012 was retrieved by Archaeologist K.M. Sandoval during the excavation of a northern Italian tomb destroyed in a recent storm. The object, a piece of handwritten musical score entitled "On Mount Golgotha", part of a larger set of sheet music, appears to be incomplete. The red/black ink, first thought to be some form of berry or natural dye ink, was later found to be human blood from multiple subjects. The first personnel to locate the sheet (Site 19 Special Salvage) had two (2) members descend into insanity, attempting to use their own blood to finish the composition, ultimately resulting in massive blood loss and internal trauma."