What is a mario level card and how do you use it?

Question

What is a mario level card and how do you use it?

Answer 1

Mario level cards are cards found in e-Reader packs with Super Mario Advance 4 for the GBA (not original or SNES version). The problem is, you need another GBA, an e-Reader which was discontinued a long time ago, and a multiplayer cable. The first level card is available with the game, but all the rest you need to find a deck of these e-reader cards.