Lanefan
Victoria Rules
By session? No.
For a particular adventure or scenario or even single combat/encounter? Yes, but very rarely, and almost without exception it's due to the party - intentionally or otherwise - being on another plane where things just work differently.
I tried (and may try again sometime if I ever work up the courage) a scenario once where a fleeing foe, followed by the party, went off-plane and into a version of Robert Jordan's Tel'heran'riod (sp?) dreamworld. Here nothing works the way you might expect...well, it does until someone thinks it shouldn't, then it doesn't. And then someone else thinks it should work a third way, and that's what happens. But thinking someone dead is likely to kill you instead; and while physical combat works (more or less) like normal, magic is another thing entirely. And as the characters (and players) quite reasonably didn't know at first how to make things work the foe had his way with them for a while; fortunately for the party he was already badly hurt and just trying to flee or else he'd have slaughtered them before they figured it out.
In the end it was like trying to DM a group-think LSD trip only without the drugs.
Lanefan
For a particular adventure or scenario or even single combat/encounter? Yes, but very rarely, and almost without exception it's due to the party - intentionally or otherwise - being on another plane where things just work differently.
I tried (and may try again sometime if I ever work up the courage) a scenario once where a fleeing foe, followed by the party, went off-plane and into a version of Robert Jordan's Tel'heran'riod (sp?) dreamworld. Here nothing works the way you might expect...well, it does until someone thinks it shouldn't, then it doesn't. And then someone else thinks it should work a third way, and that's what happens. But thinking someone dead is likely to kill you instead; and while physical combat works (more or less) like normal, magic is another thing entirely. And as the characters (and players) quite reasonably didn't know at first how to make things work the foe had his way with them for a while; fortunately for the party he was already badly hurt and just trying to flee or else he'd have slaughtered them before they figured it out.
In the end it was like trying to DM a group-think LSD trip only without the drugs.
Lanefan