This glitch will make Soma glow for as long as you want. It does nothing else (as far as I know, I could be wrong) but it does make him really easy to see. First of all, you need either the Manticore, Devil, or Curly spirits. Next, make your way to the corridor in the Dance Hall (the one that leads up to the top level of the Dance Hall). Drop down from said top level, make your way to the last door (in the background) without killing anything, face left, and press R to transform. Keep holding it until you're just over the hole in the floor, and when the game starts to change you back, let go of the R button and do a slide. Voila! The game thinks that you fell through while you were changing back, so it replaces Soma's regular image with the really bright one. He'll stay this way until you use Devil, Manticore, or Curly again.