All eyez are on Matt Barnes' right hand ... 'cause the ex-NBA baller just got the most insane Tupac tattoo!!
The artwork is crazy real ... and the story of how Barnes got it is even more wild.
The former Laker -- who's tatted all over -- was lookin' for a 'Pac piece ... and after seeing a Kobe Bryant tattoo that artist Steve Butcher did ... he hit him up on social media and locked down an appointment.
The dopest realistic tattoo artist we've ever seen flew all the way to L.