Finn McCool's Shillelagh

Origin
Fionn mac Cumhaill or in English Finn McCool was a mythical hunter-warrior of Irish mythology. The most famous story is about his childhood encounter with the poet Finnegas. In pursuit of the Salmon of Knowledge for seven years, whoever eats it will gain all of the world’s knowledge. Finnegas finally manages to catch it and asks Finn to cook it. While cooking, Finn accidentally burns his thumb and immediately sucks on it to cool down. Finnegas realizes that Finn was ultimately the one to taste the salmon and receive its knowledge.

Effects
When struck upon the ground or upon the person, can control and vibrate ligaments in the body, making until the body shakes its joints loose out of their sockets.