Bubbles

One day three ducks were swimming in a pond when a police officer pulled over the first duck.
The officer asked :
- What's your name and what are you doing here ?
The duck replies :
- My name is Quack and I was blowing bubbles in the pond.
The officer saw no reason to ask anything else so he let him go.
The officer then pulled the second duck over and asked :
- What's your name and what are you doing ?
The second duck replied :
- My name is Quack Quack and I'm blowing bubbles in the pond.
The officer then let him go as well.
The third duck swam by and the officer said :
- Let me guess, your name is Quack Quack Quack and you were blowing bubbles in the pond too.
The third duck said :
- No, my name is Bubbles.