These are beta elements from Super Mario: Wart Returns.
In 2007,a game called Mario & Luigi:Frog Trouble for the GBA was in release,but Nintendo of Hungary cancelled it because of the crappy graphics.This RPG became the game Super Mario: Wart Returns.
Five Special Worlds meant to appear,but only one made it to the final release.
Also,more Froggies would appear in the game,but Nintendo said that they are rare enemies,so there aren't much of them in the Mushroom Kingdom.
There is a green screen in the data of the game.Probably it would be a phrase of Wart or Bowser talking with the enemies in the middle of the storyline.
In the phrase,it's also said that Yoshi would appear in the game,but was thrown out.