Just while the sub (group? community?) finds its feet, I thought it would be fun to post a few challenges. I'll be searching through my house for obscure objects, to see how obvious they really are...
So, what is this thing? Springy metal, about 5cm across, with rubbery sleeves on the two arms.
The only time I used one someone had cut it out of an old soda can. It wasn't sharp but it still felt like I was a hiccup away from some cuts on my fingers.