Self-defense "fashion" keychain. This is based on one that a friend of mine has, called a "stinger." I like this design because it's just as good as brass knuckles but fits better in your pocket and doesn't constrain your fingers-- you can let go of it quickly.
Convenient hole for keychain.

If you like my designs, please consider Bitcoin donations: 1PyXaZGVyMXgAVC4xTPdu2wKwtZjGteudx

Step 1: Grip in palm of hand with point protruding between fingers.
Step 2: Bash thug.
Step 3: If thug does not go away, repeat step 2.

Slic3r tells me that there is a hole in the mesh, but it still printed fine.