Apparently for those who don't know what to do, look inside. (I'll do Carol Soon!)
If you guys STILL have Photo Dojo on your 3DS, you can use this as a fighter! For those who don't know what Photo Dojo Is: Photo Dojo is a DSiWare game that allows you to create fighters using the outer and inner cameras. You have 13 photos to take, and 10 sounds to record. Once you're done, (for those who start it for the 1st time) you can create a stage! But, It's not like Mugen. It's more or less (what I think) what the idea is for Mugen. And that's pretty much Photo Dojo!