What is fun about illusions? Fooling the players or the PCs?

[Ringlerun]

I am not up with how illusions are delt with in 3.5 or 4E but back in the day the players had to verbally say they are disbelieving what they are seeing then make a saving throw. This made illusions quite powerful, because without some reason for the players to believe otherwise the illusion would work as intended. No arbitrary will rolls for belief.

I remember a great encounter with a red dragon on a pile of gold. As the wyrm slithered down the pile to engage us in battle it made no noise. So our resident mage yells out " I disbelieve this illusion" he was quite surprised when the dragon breathed on him. It was using a ring of silence.

 

[Noumenon]

In the end, I'm gonna run the room like this: the PCs open the door and see a pit fiend with its back to them, with several bone devils in the middle of the room worshiping it, plus all the mirrors showing more bone devils, giving kind of a cybdem_boh.gif effect. See what the PCs do when they seem to have intruded on thirty bone devils and a pit fiend. Figuring out that the pit fiend is an illusion and all the bone devils but one are mirror images -- that should be fun. Or they might just give up.

Edit: it will also give me a chance to let the players see the proprietor of the prison (the pit fiend Bazgorca) for some neat foreshadowing. The bone devil will be worshipping the illusion trying to prove Bazgorca shouldn't imprison him any more.

 

[DnD_Dad]

In the great old deck of encounters there is a goblin being chased by and ogre. He runs to the players screaming, turns around and blows the ogre up with his "magic wand." of coarse it's all an illusion and the goblin just wants to get out of fighting the party, an maybe get a small toll from them on top of it. Pretty fun use of an illusion.