Naturally it seems like the most common of all back of head tattoos is the creation of a face, often very sinister and evil looking, or perhaps something less morbid like the state of Texas or maybe ever a funny design like a small lawnmower like we see in the picture below.
Scary face with multiple eyes and arms.
Funny idea photo.
Evil face with tribal and dragon designs.
Scary skull on guy with pierced ears.
Freaky zombie face idea.