A few thoughts on the containment procedures. Is the requirement of one single light to ensure that the SCP is always casting a single shadow? What would happen if multiple light sources are used, or if all lights are turned off? It seems to be implied in the test log, as the test immediately jumps to using the one light (just for the duration of the test). Is 1 cm of sand enough - what if enough sand is pushed aside that the shadow starts affecting the floor?
Also some questions on the invisibility effect. If a D class grabbed onto the SCP, would they become invisible? If a rope was tied to a D class, then tied to the SCP, would that turn the D class invisible? If someone is invisible due to that effect, can they see the SCP? If the SCP punches its hand into a wall, does the wall (or the whole building) disappear?
I thought the last log was good enough, and implied what was happening well enough based on the results of the other two tests. Guessing that the SCP moving its arms would tear the skin off the D class or something, as I imagine the shadow only affects the surface.