Scratch

Alright, if you click the link, you won't regret it.
Megaman Vs!
If you ever wanted to play Megaman with different bosses... Well, here you go.
Even if you don't like Megaman you'll probably like this.
http://scratch.mit.edu/galleries/view/125820
If you want to see your favorite character as a boss, then let me know!  I need more ideas anyways  .