Wow, very informative and useful thread! Thank you, Jondor_Battlehammer, for reviving it... my players won't thank you, I'm afraid. 
Just off the top of my head, I'm thinking I'd make a chest or other loot appear (or augment existing loot with more pieces). Just to be mean, I'd then have a wall descend slowly from the ceiling of the hall behind the escaping NPC (ala Indiana Jones).
Or I'd put the illusion of a dead NPC (either the one they're chasing or a henchman they've seen before) on the floor. They know he's carrying goodies, and with their current obsession with the MIC and constitutional inability to leave any dead bodies unlooted, they'd be bound to at least stop to check it out.
How about a gorgeous woman, tied hand and foot and gagged or unconscious, in a cage about thirty feet off the ground? My players are pretty chivalrous; they'd probably stop to help her out. Especially if she looked rich. Or if the cage looked as if it were about to plummet to the ground...
Or have the tied up captive be someone dear to the PCs. Especially shocking if the PCs aren't aware that the villain knows them that well (I once had an NPC arrange for a rose to be placed on the pillow of each of the PC's girlfriends -- a subtle warning that he could get to them whenever he wanted. The PCs were *not* happy).
"This spell creates the visual illusion of an object, creature, or force, as visualized by you." Forgive the probably dumb question, but what does the 'force' part mean?

Mistwell said:So what sorts of illusions can people think of that could be done with the silent image spell that would be likely to deter opponents from pursuing by that route, but which are not a "wall", and apparently which are not a spiked pit. We have a creature, and bubbling lava pit (though that will have no heat and no scent, so it won't deter anyone for long). Anything else?
Just off the top of my head, I'm thinking I'd make a chest or other loot appear (or augment existing loot with more pieces). Just to be mean, I'd then have a wall descend slowly from the ceiling of the hall behind the escaping NPC (ala Indiana Jones).
Or I'd put the illusion of a dead NPC (either the one they're chasing or a henchman they've seen before) on the floor. They know he's carrying goodies, and with their current obsession with the MIC and constitutional inability to leave any dead bodies unlooted, they'd be bound to at least stop to check it out.
How about a gorgeous woman, tied hand and foot and gagged or unconscious, in a cage about thirty feet off the ground? My players are pretty chivalrous; they'd probably stop to help her out. Especially if she looked rich. Or if the cage looked as if it were about to plummet to the ground...
Or have the tied up captive be someone dear to the PCs. Especially shocking if the PCs aren't aware that the villain knows them that well (I once had an NPC arrange for a rose to be placed on the pillow of each of the PC's girlfriends -- a subtle warning that he could get to them whenever he wanted. The PCs were *not* happy).
"This spell creates the visual illusion of an object, creature, or force, as visualized by you." Forgive the probably dumb question, but what does the 'force' part mean?