Paper Mario: The Thousand-Year Door
July 22, 2004
In Paper Mario: The Thousand-Year Door, some time after uncovering the fake Zip Toad on the Excess Express, Mario receives an e-mail of thanks from the real Zip Toad. At one point he tells to be going to star in a movie titled "On Golden Toad 2", a very likely pun on the movie "On Golden Pond".
Note that Zip Toad's mail also features a reference to the movie The Road Warrior.
Mario's company Nintendo held no right over Ernest Thompson's On Golden Pond, but they only included a minor reference.