Does anyone know where the weird mandela effect of thinking Wario is Mario's cousin came from?

[Ultimatevaltryek123]

For some reason most of the Mario Fandom seems to think Wario is Mario's Cousin even though other than that Wario has a childhood beef with Mario that causes them to be enemies as adults (And some stuff that varies depending on the version of the Mario Universe)

 

[Princess Viola]

I have literally never seen this supposed Mandela effect before.

 

[Sprig]

Could of sworn I saw this somewhere actually. Maybe it's in the manual for SML2?