This a cardboard version of the wolverine claws wthat when you move your hand the claws come out, after watching the movie I got the idea of making them, I'm sure you can make them better but this is just to give you an idea how a the mechanism works.

http://www.youtube.com/v/LR8A6fCtV6E&hl

Step 1: Getting the Materials

Here you will see the materials you will need and how to cut the cardboard to make the claws

cardboard
scissors
a piece of string
3 rubber bands
1 craft stick
1 round head fastener

Step 2: Putting the Claws Together

first you have to put the claws together by attaching the claws to the bend piece of cardboard, as it shows in the picture
after that you will have to tape them, you can cover them with aluminum foil if you want but thats up to you.
also ad the 2 rubber bands on the 2 external claws.

Step 3: Making the Box

the interior of the box has to be a bit bigger than the width of the claws assembly so it can move freedly inside the box, also make sure that the grid where the claws go throu, is about a 1/4 of an inch so the claws wont get stuck there,
also add the fastener 3/4 of an inch from the end of the box, and in the center thats the part that will be holding the rubber bands, you can see that in the picture

Step 4: Adding the Claws to the Box

once you put the claws in the box as it shows in the picture, you can connect the rubber bands to the fastener and add the top piece of cardboard

Step 5: Tape the Box and Get Ready to Use

this is the final step you will tape the top cardboard, and the craft stick with the top cardboard to give the box more strength ,
then retract the claws inside the box, and put the cardboard with the string attach to it between the claws and the box as it shows in the picture , tape the side the doesnt have the string to the front side of the box,
then add a rubber band around the box, so it can be hold to your and and put the string around your finger, so when you close your hand the claws will come out :)