This article is from the 2006 series of SMBZ and is no longer canon.
The Super Leaf is an item first found in Super Mario Bros. 3. It also notably the most abundant or common item in the game. The power-up transforms Mario into Raccoon Mario, as the same for Luigi too.
In Super Mario Bros. Z Episode 8, the item gave Mario lots of new abilities and made him more powerful than he was in the past, but still gains its original abilities, such as spinning and flying. In Episode 4, it made its first appearance in the intro.