Ok, so here's my theory.
I see these people coming in to my store yesterday with ashes on their foreheads. And my mind starts spinning. Ashes, huh? What is this all about? And then I realized that I could do the same with coffee grounds. So I put a mark of espresso ground coffee on my forehead- so I could fit in and see what it feels like. And then I started thinking... wait, it's just like coffee, except it's burnt. Burnt coffee... burnt coffee...
STARBUCKS!
So I'm thinking that maybe this is a ploy. Maybe Starbucks has infiltrated the Catholic church and is putting the ashes from their burnt coffee on the Catholic people. It's a sign, like the lamb's blood on the door frame at Passover. Maybe someday, Starbucks will decide to do us all in. All of us that aren't Starbucks people; all of us without the ashes of burnt coffee on our foreheads. I don't know... I'm just thinking.
But I think, if you look really closely, you'll see that those ashes are not in the form of a cross at all, but in the shape of a mermaid.
A MERMAID!!!

(If Howard Schultz turns out to be the next Pope... well, you heard it here first.)