Terrible, Awful Pony Jokes #2

Pinkie Pie watched as the Mushroom Brothers, two mushtachioed plumbers who wore color-coded overalls, crawled out of Ponyville's only gunge pipe, covered in filth, muck, and crap. Covering her mouth with her hoof to hide her mischevious smirk, she bounced up to them, and asked:

"Who do doo-doo on you two?"