[Cerek the Barbaric]

Speaking of elves and infravision reminds me of a module I once ran for our group.

I had decided to allow the players to create their favorite character and lifted the demi-human level restrictions (I allowed one player to play a minotaur barbarian - he was as strong as an ox ).

Another player created a drow fighter/thief (or something like that). The module had the characters go to this little wide-spot-in-the-horsetrail town that USED to have a small keep located on hill (basic medieval set-up).

The foundation was the only thing left, but there were four pits/wells/holes/whatever where the four corners had been. All four had water at the bottom. Two of them had nothing of interest, one had a gelatinous cube lurking in the water, and one hid the secret entrance to the basement of the keep (which was still intact and still had some treasure stored there).

The drow volunteered to scout out the holes because he had infravision (AND because the PLAYER had read the module before and knew there was a monster in one of them). He checks the first two with no luck. Then goes down the third. There was a rather nice magical item at the bottom of the third hole (which is why the gelatinous cube was there). Now the player knew it was there and he also knew there was some kind of monster that was practically invisible.

So he says "I climb down the ladder and stop just above the water. Looking down, what do I see?"
ME "As you look into the water, you notice something shiny at the bottom of the hole."
Player: "Do I see anything else in the water? Any kind of creature or monster?"
ME: "No."
Player: "OK. I'm going to use my DROW VISION! NOW what do I see?"
ME: "You still see shiny object at the bottom and nothing else."
Player: "But I'm using my DROW VISION!"
ME: "It doesn't matter. All you see is the shiny object in the water." (BTW, gelatinous cubes are transparent and give off no body heat. Put them in cold water and they're virtually impossible to detect).
Player: (upset because he KNOWS there is a monster there) "But I said I'm using my DROW VISION!!!"
ME: "And I said that you see something shiny in the water and nothing else."
Player: (irately) "BUT I'M USING MY DROW VISION!!!! IF THERE'S SOMETHING THERE...I SHOULD SEE IT."
Meexasperated) "OK.....using your DROW VISION....you STILL see a shiny object in the water and NOTHING MORE."

The player finally just gave up and climbed out, but we razzed him about his DROW VISION for weeks after that.