Lemmy Koopa is the second oldest of the original 7 Koopa Kids, and a reskin of Bowser Jr. in Super Smash Bros. for 3DS and WiiU. His usual attacks go hand in hand with Bowser Jr's, but outside of the fighting arena, he usually balances on a ball and throws bombs at people, just like his hero and Godfather Mouser.
Lemmy has been around since 1988 in Japan, 1990 in the US, and is physically only 7.