As he would say "bwoo bwoo bwoo bwoo bwoo!" - or however it goes. :)
Step 1: The Pieces!
Hot Glue Gun
Bart Simpson Mask
Red Face Paint
4 Pieces of Red Felt
Lab Coat (embroidered)
A Dude with Dr. Zoidberg's stature
I ordered a Lab Coat from AllHeart.com or something like that, and had it embroidered with "Dr. Zoidberg".
For the Claws, he bought a hot glue gun and some felt and I was kinda puzzled as to how to make them .. cute/realistic/wearable, just make sure to have good scissors, stack the felt 2 at a time and wisely cut so that the 2 pieces match up. I used elastic to keep them on his wrist and stuffed them with polyester fill, to make them more functional.
For the FACE...lol..we lucked out. Tripped over a bart simpson mask at Target and we ended up making the eyes into the shape of goggles, leaving tabs on the side for elastic attachment to hold them onto his head.
The "mouth fingers" were a pair of women's gloves. (I cut the thumb off and hand sewed it shut and then took the part and attached it to ITSELF in the back, behind the mask, also stuffed the fingers a little.
Step 2: Party!
Now it's time to hit up Comic Con, or the Halloween party, or whatever you want to do as Zoidberg. I made this costume for him in 2007, and I had a video of him doing the sideways walk...but I can't find it and that saddens me! Either way, he loved it and people still ask my brother "how is Zoidberg?" after that party that night. (3 years ago!) :D Zoidberg lives on.