The close-ups of the chompy little muppetized fish.
The camp counselor dragged down into the depths of the lake. Tragically, her life preserver was not that helpful.
The lone loser in the canoe, rising to the occasion and saving other campers.
And the fact that everyone in the movie--and I do mean everyone--apparently already knew that "piranha" is plural for "piranha."
"Sir, piranha have infested the lake!"
"Piranha, you say? How many?"
"At least ten thousand piranha, sir!"
Not one single character ever says "piranhas," but I imagine if they did, someone else would say, "Oh, didn't you know? Piranha is plural for piranha. Like moose." At which point a grateful audience says, "Ahhhh, I got it."
I'm very excited for the new 3D movie, in case you can't tell.