Duck is a very lame, boring, easy, or useless thing. It's mostly used as an insult, or to say a person isn't very cool or nice.
Hero is an
interesting, yet
difficult thing. It's used to say something or someone is
really cool, nice, or poular
Duck to Hero is a term used as a scale measurement. It would be used to compare things.
"On a scale of Duck to Hero, how hard do you think
the test was?"
"That swim
practice was really Hero, we had to swim a 200
butterfly."
"She's such a Duck! She didn't know what -9+-7 was!"
OMG! Suzy is such a Hero! She is like, the coolest girl in the grade!"