From Smash Wiki:
Giant Mario Head: "Ooh, very scary."
That, or he saw the "You cannot beat us!" commercial on a trip to Australia.
Giga Bowser was created due to Masahiro Sakurai's interpretation of Bowser's 8-bit sprites as a "frenzied, terrifying monster"
Giant Mario Head: "Ooh, very scary."
That, or he saw the "You cannot beat us!" commercial on a trip to Australia.