They may be entirely fictional characters but it's fair to assume that in Super Mario canon, the famous Italian siblings must have a father - but Nintendo has never really acknowledged the fact. Or has it?
Reddit user l33tredrocket appears to have found evidence that Mario and Luigi's papa does indeed exist in some form - the form in this case being a metal tray which formed part of an early Mario Bros. merchandising push.
The tray shows the brothers in their home, with a strangely-rendered Bowser emerging from the TV set. Putting aside this rather worrying image for a second, we spot a portrait on the wall which features a man who looks very much like Mario but has grey hair and is dressed in blue overalls. He's also smoking a pipe, just like wise old dads do. We think.
Another Reddit user - Inkwild - has taken this basic headshot and created a full-figure image of the mysterious "SR".
It's highly likely that this character exists only in the imagination of the artist who created this particular piece of long-forgotten promotional artwork, but just think - someone at Nintendo will have signed off on this, which - for some fans - is enough confirmation that "SR" (Super Reginald? Super Ronald? Super Rodriguez? Or perhaps, just plain old "Senior"?) is indeed the dad of the world's most famous plumbers.
Thanks to Arjun for the tip!