Not since I was younger have I seen a pair of "tighty whiteys" that don a Nintendo character. Etsy user "lastactioncowboy" drums up some fond memories of yesteryear with these size "M" Piranha Plant Underwear. If you fit the bill, then head on over and pick up one of only five. Of course, if you love to live a bit more free, you could opt for official boxers...

Link: etsy.com