The weird scuffling blue robot was someone in a tachikoma/logicoma cosplay costume, on their hands and feet, which, if you watch it in reverse and change the costume to something far darker, glossier, and dripping with K-Y jelly, is how they tried to do the alien special effects, if you've seen the outtakes. It ended up looking like someone walking on their hands and feet, which is why they ended up not going with it. I thought the cosplay a bit better. Compare: