The body in the bathtub
The clip can be viewed on disc 4 during the "Nexus Generation" featurette.
My interpretation is that it's one of Sebastian's projects that he has discarded. But he was too cowardly to dispose of it properly. Kind of like leaving an unwanted infant in the woods. There is no blood and the decay looks very plastic-like. I'm sure it's a "toy".
Sorry if I missed any topics on this. What exactly are we dealing with here? Thanks!
PS. I just found out that this is all part of the "That's the spirit!" scene. Amazing...the level of detail in this film.