... spray paint?
http://www.kidmerc.com/
Excuse the horrible website.
All done with spray paint. We (my family and I) have 2 paintings from them, and my little brother and my moms boyfriend both have a bass drum head painted by him. They all look incredibly amazing.
Some of his tools:
-Spray paint, lots of it.
-Paper, LOTS of paper. (He puts the paper down over several layers of spray paint and blotches it up, and it looks really cool, alot of the planets he does, he uses that technique. He also puts his fingers down on it, and slides the paper out from under his fingers while pulling it across several layers of spray paint to make it look like mountains.)
-Circular discs (to make planets and such.)
-A fine pointed triangular shaped "pen" almost. (He makes that for staircases and such.)
Check out some of his work, he's really talented.