It's foolproof.
4 seconds sound clip from the Finding Nemo movie soundboard.
You can hear this line at 00:40:00 in the Blu-ray version of the movie.
Quote context
[...]
- What we need you to do, is to take a pebble inside there and jam the gears.
- You do that and this tank's going to get filthier and filthier by the minute.
- Pretty soon the dentist will have to clean the tank himself.
- And when he does, he'll take us out of the tank, put us in individual baggies...
- I.
- I think you're nuts. (SIGHS)
- No offense, kid, but you're not the best swimmer.
- So, Sharkbait, what do you think?
[...]