The most impressive thing Baltimore Ravens backup QB Robert Griffin III has done in years is get this crazy Hulk and Goku leg sleeve tattoo...
We're told Griffin is a HUGE fan of cartoons and comic books ... and hit up Nic Westfall recently to immortalize his love for some characters on his left leg.
And, it's clear the artist didn't disappoint ... check out the piece -- Goku and Hulk look real as hell!!!
In total, Westfall tells us Griffin sat for 10 HOURS to get the tat done ... and says the former Heisman Trophy winner is still planning on adding more to the piece this offseason.
Westfall says RGIII wants some Teenage Mutant Ninja Turtles on the inside part of his leg -- and tells us the QB could add some more Dragon Ball Z characters too.