Yes, believe it or not, there have been times in the Super Mario cartoons when something occured, and it hadn't even appeared in the games yet! Here's proof:
On the SMB Super Show!, the Koopa Troopas walked on two legs, which they wouldn't be doing in the games until Super Mario World.
In "Brooklyn Bound", Mario flies up a chasm. And Super Mario Bros. 3 wouldn’t even be showcased for two more months!
In "The Mark of Zero", Mario and Luigi use capes to fly into Bowser's fortress.
In "Plummer’s Academy", there are two plumbers who look like Wario and Waluigi.
At the beginning of "Raiders of the Lost Mushroom", Team Mario is travelling above Jungleland in a hot-air balloon with a big red "M" on it – the exact same mode of transportation used in Super Mario Advance 2!
"Sneaky Lying Cheating Giant Ninja Koopas" may be where HAL got the idea for Paper Mario's Ninjakoopa Bros.
In "Fire Sale", Yoshi seems to be afraid of water. The coincidence here is that in Super Mario Sunshine, the Yoshies on Isle Delfino couldn't stand water either!
The giant Piranha Plant in "A Little Learning" may be the predecessor of Petey Piranha in Super Mario Sunshine.
Super Mario Bros. are cool like sunglasses!
