"Outta my way, stupid duck!" shouted Bob, kicking the duck.
Bob didn't know very much about waterbirds, but what happened next would surprise even an ardent member of the Audobon Society. Instead of flying through the air, as one would expect a duck to do when kicked, the duck didn't budge. Bob's foot bounced off of it, as if magically repelled.
"Whoa," thought Bob. "That's weird."
He tried touching the duck with his hand, only to have it similarly repulsed. It was like touching opposite magnets together. Curious, Bob tried kicking the duck again.
"I really wouldn't do that if I were you," spoke a voice from behind him.