How do you make the 'guy' invisible?

In a special item room with a guy, how do you make the 'guy' invisible?

You can delete his tile. :p This is probably best done with the "Fire" Guy though. On the very first Tiles page, (Tiles Page 0.) just delete the fire tiles you see near the middle of the upper left quadrant of the tiles page. You can make a backup of them by copying and moving them somewhere else in your tiles page, of course. Then, obviously, under "Guy," just select "Fire." Fire has no tiles assigned to it, (Or simply consists of nothing but invisible pixels. :p ) So it'll be invisible.

In 2.11 Beta 9, I think there's also a quest rule "No Guy Poof" and "No Guy Fires" which will help make the screen more realistic looking.

Ok, I'll give that at try. Thanks! :)

Just so you know, "No Guy Room Fires" is a rule you can check in 2.10, and even 1.92, I believe. If you check it, then choose Fire as your guy type, no guy will show up, but you can still have the special room type and string work correctly.