What is the biggest tattoo that someone got a one time?

Its not the biggest you can get at one time but how long you can sit in the chair doing basically nothing while a artist is stabbing needles into your arm for hours on in. My personal limit is 4 hours but Some people I know have gone for 12 hours with 30 min breaks in-between. It can get pretty big but won't be finished. Also depends on how fast the artist is and the quality his work is. Research before going into it.