The Mario series is the most represented series in Smash Bros. so far, with a grand total of 5 representatives (8 counting Yoshi, Wario and DK). But still, one major aspect of the series is missing. That aspect is the enemies. Over the years the Mario series has featured a large range of diverse enemies, but they have still not been represented in playable form. This must change.
Goomba: Almost no chance of getting in, due to his lack of arms or method of attack other than bumping into people.
Koopa Troopa: Quite a high chance: he is iconic, has appeared in many Mario sports games, and his shell would allow for a very interesting moveset.
Hammer Bro. While not as well known as Koopa Troopa, still very iconic, and he appeared in Brawl as an assist trophy.
Goomba: Almost no chance of getting in, due to his lack of arms or method of attack other than bumping into people.
Koopa Troopa: Quite a high chance: he is iconic, has appeared in many Mario sports games, and his shell would allow for a very interesting moveset.
Hammer Bro. While not as well known as Koopa Troopa, still very iconic, and he appeared in Brawl as an assist trophy.
Besides, shy guy should be a yoshi thread character.