TORX BITs.
They are the devil.
Whenever I buy them I get numerous sets because it seems when you need them you need them and then you bust them left and right!!!
The front caliper bolts on my truck were torx, found that out the first time I went to replace the pads at 70k. I went to a couple different auto parts stores until I found replacements with normal hex heads and replaced them so I wouldn't have to carry that one torx bit in my tool kit.