Let me start by saying, I'm not Catholic.
However I can appreciate lent and the other things Ash Wednesday is about... like creating a day it's acceptable to show up to church in full cosplay. There are so many options, but the two most obvious are Wednesday Addams, and Ash Ketchum.
So here's a few little GIF's to brighten up your Ash Wednesday.
You made it through today, congrats. Now just remember, even though its cool to cospaly at church today, it's still rude to play Pokemon on your 3Ds in church.