Here is me and my friend Bryan, who was Dexter, the lovable serial killer.
The mask was pieced together using a pair of knit caps sewn together, with the top on one opened up along the seam to create a neck opening. A glove made a perfect set of mouth tentacles. Holes were cut to see through (buttonhole stitched to keep the knit fabric from fraying/unravelling). Ping pong balls with about 30% cut off and with holes added for visibility (and to create pupils) finished things off.
The claw is articulated and fairly complex. I used my papercraft skills to shape the base out of cardboard. My original plan was paint it, so I then added a few layers of papier mache to smooth things out and have a white base instead of brown for painting. When I couldn't find paint to match the mask, I decided to cover it in fabric. Unfortunately, I ran out of time and could only make one claw. I just went with the story that the other one had gotten caught in a dumpster and hadn't grown back yet.
Oh, and you can't see it, but I found perfect pink slippers that looked like Zoidberg's feet in sandals. So, uh, now I have pink slippers to wear around the apartment.