My DM and I have been trying to come up with a cool (and balanced) way to give my character (Level 7 Arcane Trickster) a magical tattoo used to cast Find Familiar, but have not yet come up with any interesting way of doing it. Beside just learning find familiar and getting a tattoo for flavor, what's an interesting way you would handle something like this?
I love magical tatoos as magic items. I even DMed a wizard PC who had her 'spellbook' inked all over her body. I also played a monk who had bracers of defense as a tat, not actual bracers. He also represented (ie: fluffed out) his growing monk class abilities by giving himself new tattoos durning his 'down time'.
Personally, I'd make the tat the familiar. It springs onto/into and off of the PC's skin at will. That way, the PC is never without the familiar, and the familiar has a cool flavorful way of 'retreating' if it gets killed or lost. You could still follow the full rest rules, attunement, or whatever is in the PHB about familiars (I forgot, and don't have the book open ATM)...If you and your DM want to 
Now, if the PC gets the tattoo burned, amputated, flayed, rotted off,etc. then the tat could be distroyed, and another method of gaining a familiar (or the find familiar spell) might have to happen. But, again, that'd lead to some cool story or adventure ideas.
For the most part, magical tattoos is just fluff. I really cant think of mechanical changes that would benefit or reflect that type of change other then good fluff of how things happen.
Somewhere I read, and I do not recall if it was this version or even this game, but something said that the spellbook of a wizard can be anything, including tattoos. However, as cowleymen states, its generally fluff.
Vague movie reference, but wasnt it the sorcerer's apprentice, that had the one evil guy that had the tattooes on his body and would summon them out?
Phobos wrote:
Also in the Elektra movie, there was a guy with several tatoos that he could send out off his body.
Knight_Marshal wrote: