The Armadillo costume idea came about from real life inspiration. When one of the writers tried to rent a clown costume for his nephew's birthday, the costume store was out of clown suits. He asked what else they had that was funny, and the clerk showed him a giant armadillo costume because it was so ridiculous.
The Magna Doodle has ducks flying up into the air with hunters hiding in the tall grass and shooting at them.
Cole Sprouse's character in this episode of Friends, as well as in Big Daddy, was subject to a costumed adult trying to convince him of something he didn't believe in.