You could shoot a rocket filled with some sort of paint/stain directly at the moon. If you made a large enough splatter it would be visible from everyone on earth and get folks mad/go viral.
This sounds like a question for Munroe’s What If. My completely uninformed guess is that it would take many rockets to make a sufficiently-large splash.
I agree. The surface of the moon is 4E7KM^2. Assuming you paint only one side it's slightly bigger than the surface of Russia.
It's silly to paint near the border of the visible side because the surface is almost tangent to the line of sight. It's better to paint the central part and keep the border white. (It's also better if you want contrast with the background or your logo has a withe circle around it.)
Anyway, painting only the central half of the visible surface, it's 1E7Km^2 that's slightly larger than the surface of Canada=China=USA.
You would not need to paint the entire visible surface, you could settle for filling in a crater like Tycho (which is smaller than the state of Delaware). That would still get folks super mad!
Calvin and Hobbes was also a major source of happiness during my youth. At one point I think I could have quoted you every strip.
I fancied myself an artist when I was a kid and had a regular comic called "Teco And Jix". It was an obvious ripoff of both Calvin and Hobbes but had very violent storylines. When it came time to create my first "internet name" (for AOL AIM), I went with TecoAndJix and it has remained my digital pseudonym to this day! I even got it tattooed one not-sober evening in the Navy...
I feel silly now. I downloaded the app after the announcement (I'm a desktop user) and it looked identical to the one they show in the sarcasm video. When I asked it, I was told it was not the new feature announced yesterday. Still a lot of fun!
Edit - it does list the new model in my app at least