Dremel tools. They're good at inflicting injuries because they're so damn fast. I never use mine at less than 15000 RPM, and when I'm doing something heavy duty, I crank it up to the full 35000 RPM and let 'er rip. Sadly, my Dremels seem oddly attracted to the tender pads of my thumbs. Healing time measured in weeks, scar duration apparently infinite.
Bob Schultz
Yep, Dremel cut-off disc meets left thumb. Through nail and down to bone in a fraction of a second. #askhowIknow