From the Shirtpunch.com's interview with the artist:
"Question: What inspired this design?
Answer: Believe it or not a vintage pop-eye shirt I found at The Gap! I also got this wild idea to draw Doc Brown like Dr. Wily from Mega Man. I always secretly wished they would have made an anime out of Back to The Future!"
About Shirtpunch.com: It's simple; ShirtPunch is your home for limited edition, pop culture tees... but there's a twist! We only offer one shirt every 24-hours, and they're always only $10.