If you haven't seen the movie yet, we're about to talk about something you probably don't want to know about. Right, with that out of the way, here's the scoop...
Spoilers ahead! The Mario Movie features certain characters in Mario's family tree we've never seen before, including his parents, uncles, aunts, niece, and even his grandfather. So how did it come to this?
Speaking to Polygon, the animation's directors Aaron Horvath and Michael Jelenic mentioned how they wanted a family dinner to help set the scene and Nintendo was "completely open to it" providing some unreleased sketches to help out.
The design of Mario's "Mom and Dad" ended up being "very close" to Nintendo's unused versions, apparently. In fact, his father in the movie is described as being a "one-to-one" design adaptation of Nintendo's original, and Mario's mother only had a "few" changes to her.
With some other family members, the movie team strayed just "a little bit" from the original designs.
"It goes back to […] grounding the characters... We wanted to have them at a lively family dinner scene. So it’s like, Well, we need a bunch of people — who would be there? Mario’s mom and dad. He was going to have a couple of uncles who were like, you know, breaking his balls. Those are his dad’s brothers, [Uncle Arthur, played by John DiMaggio, and Uncle Tony, played by Rino Romano], and his aunt Marie.
"Nintendo were completely open to it — they were fully on board with this cinematic representation of Mario... So they were totally on board with creating this family for Mario... They did send us character sketches that they had done years ago that they had never used.."