Having approached things a bit cautiously for the start of the adventure we became a little cocky about not having taken any damage in the adventure after a few fights. The Ninja and I swam through a small pool of water to scout out possible exits to the room, and were attacked from beneath by a Sahaugin and a shark. The shark nibbles the Ninja's legs, and he becomes the first member of the party to be injured so far (except for the unfortunate puking incident, which also involved the Ninja). The DM rolls some more dice behind his screen for a second attack and sucks some air through his teeth after seeing the result. I muse that 'it's always funny when it happens to someone else'.
The DM doesn't look up from the book he is consulting to see how much damage he is about to inflict when he says, 'This is happening to you'.
'Oh.' Everyone else found this amusing, so in a way I wasn't wrong.