Before getting the 666 tattoo, get a Ph. D. in psychology then get the tattoo on your forehead. Then write a book about everyone's subconscious reactions to you and your new tattoo.
This, I believe, will be a name with six letters in each name invisibly coded into the laser tattoo or micro chip. A computer could pick this up as 'six digits' in each name.
The number 666 invisibly coded into the laser tattoo or micro chip and placed on each person in the form of the UPC barcode mark
Rev 13:17 And that no man might buy or sell, save he that had the mark, or the name of the beast, or the number of his name.
Rev 13:18 Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a man; and his number is Six hundred threescore and six.
I think you mean "mark of the beast"? well no. All you're doing is putting ink into your skin -- it doesn't matter what you actually get. Only problem you need to consider is that its stuck on you the rest of your life. I love tattoos...but 666 the devil's sign?????????? What happens if down the track you discover God and you have to carry around this horrible reminder of you past life forever? Just get a nice butterfly or a dolphin =P