I dunno more or less if your like me you go with the flow and put your ideas out there...
The challenge is basically making your O.C or any character that you like from an anime/manga/game be dressed as whatever other character you can think of may it be from a movie, game, anime etc
Just have them dressed as someone or something else
These are the best things i can find as examples for you to get an idea.
Be as creative as you can. More than one character if you want. At least up to 3 entries. Follow theO rules and also it can be digital or traditional...
1st place: Drawing (character of your choice) colored and a gift
2nd place: line art drawing (character of your choice) and gift
3rd place: line art drawing (character of your choice) and a gift
3months is what i give you because as i said this is just an Idea