Chris Eckert has made a cool CNC tattoo machine that offers automatic Tattoo with its auto ink that designed with three axis numerically control.
Automatic-Tattoo-Machine

CNC tattoo machine will automatically tattoo corresponding symbol on the arm, once the main switch is triggered, it could either randomly pick a symbol for the tattoo or assigned the symbol of your choice.

[ Source: LikeCool ; Chris Eckert Blog ; Chris Eckert Gallery ]