Pencil-Faust

what you need:

• Toy gun caps (you can get them from the 2 dollar store)
• A pen or a tube similar to the radius https://ie.dhgate.com/product/gel-pens-european-standard-pen-0-5m-point/872045087.html?skuId=1124515696036073514
• A spring (x2 from a broken lighter) or you can get it from a pen spring (x3)

the tutorial :

I do have a basic intro vid to it: