This should have been posted in General Mario Chat, but this is a reference to Professor E. Gadd. He made Luigi's Poltergust 3000 in Luigi's Mansion. The game is hinting that Gadd also made FLUDD and the brush. If you look at the icon on the nozzle boxes, it looks like Gadd's head, which makes it obvious.
Don't worry about being new. I am too. Tips for not being a fool: don't post and outrageous number of topics. Replies are fine, but don't reply to really old ones unless you have a good reason.
Got Bird? -Bird Person<(^v^)>