After they dry, put them together with the painted sides facing outward. I initially thought of gluing or stapling the plates together to hold them together firmly. Instead, I made holes on the edge around the plates wherever I wanted a leg, eye, or arm. Next I took a pipe cleaner and bent it in half like a V. Stick the pipe cleaner so that it goes through the same hole in both plates, until the bend of the cleaner is in the hole, then take the 2 lengths of the V and twist them together. Not only did this "tie" the plates together, it made the legs a bit more sturdy than just one simple pipe cleaner.
To make the grabbers, just use the same technique as the legs. After the pipe cleaner is twisted together, fold it back onto itself a few times to make a pincher shape at the end of the arm. For the eyes, stick them straight up and glue a pair of googly eyes on the ends!With a little determination and plenty of careful maneuvering, you can get the crab to stand on it's own!
The kids had fun with this craft during our Oceans unit. A couple of notes - some of the kids put the paint on pretty heavy. This made some of their plates warp or flatten a bit, and their crabs turned out either flat, or...well, just kind of odd. They loved them anyway! Just be aware.