"You don't know it yet, but I'm the real reason you're here... Check me out! No, seriously, check me out."
Strong Bad is one of the core characters from the wonderful web cartoon Homestar Runner. While he primarily acts as a self-proclaimed "multi-purpose criminal element" and antagonist to Homestar and his friends, it could easily be argued that Strong Bad is the real star of the show.
Much like the other characters on Homestar Runner, Strong Bad is quite peculiar in apperance. He has a rounded body, and an egg-shaped head. He appears to be wearing a lucha libre-inspired mask and boxing gloves, but supposedly that's what his hands and face really look like. He also walks around in black pants and red boots with no shirt.
Strong Bad is everything you could want in a villain, or at least that's what he'd like people to believe. Sarcastic, callous, egotistical, and frequently scheming, Strong Bad is the token pathological id in every web cartoon. He has a vaguely Hispanic accent, "rules" his own country of Strongbadia, and thanks to the jewel on his forehead, he can open bottlecaps and knock off Homestar's hat with the power of his mind. Utterly convinced of his own coolness, Strong Bad likes to think of himself as the ultimate ladies man as well, though Marzipan, the only female character on Homestar Runner, doesn't like him in the least. He's brother to Strong Mad and Strong Sad, and employs The Cheat variously as a lackey, best bud, and pet.
Being the bad guy keeps Strong Bad busy. His various pursuits include answering his fan mail in the famous Strong Bad E-mail segments, making prank calls to Marzipan's answering machine, and picking on Strong Sad, Homestar, Homsar, or any other available target. His pet peeves include Strong Sad's whining, bad spelling and grammar, and people who e-mail him and ask "how do you type with those boxing gloves on?". Strong Bad is more than just a troublemaker, though. He's also a multi-faceted artist: he's the creator of Trogdor the Burninator, the independent comic Teen Girl Squad, the crazy cartoon Sweet Cuppin' Cakes, and his anime alter-ego Stinko Man, and is also an accomplished musician (he contributes several songs to the album Strong Bad Sings) and actor (witness his role in the Dangeresque series). He's also the star of his own video game, Strong Bad's Cool Game for Attractive People. So perhaps there's more to Strong Bad than just being an egotistical jerk...
But not much more.