Who was the first character cast in the Harry Potter movies? If you guessed Hedwig, you're right. And that's not the only fun fact about magical and otherwise imaginary creatures from this great TopTenz list.
Here's another great trivia tidbit -adorable little Gizmo from the Gremlins was originally supposed to become the antagonist, but Steven Speilberg decided (rightly) that fans would prefer to see the adorable little creature as much as possible in the movie and wouldn't want to root against him. Just imagine what a different movie it would be if little Gizmo was the enemy.