Given the amount of empty space in Lavos, combined with the fact that it lives deep underground, it's likely that the pressure inside it's body would be different from the outside and therefore quickly removing it's head would probably create a popping noise, right?
Ryan, Sadly I thought exactly that when I read her line ^_^
How did she kill Lavos that easily?
I think a whooshing sound effect may have been more appropriate, but not as funny as pop.
That's just like BnG with the 'pfoof' sound effect...
@neospyke: She didn't kill Lavos. All she did was remove the "head" of the shell, giving her access to his core.
The "Pop!" Let's you know that even after many millions of years Lavos is still fresh!