Halloween - DM plays PCs, Players play monsters?

[Halaster-Blackcloak]

Has anyone here ever run a game like this? I've been wanting do try this for some time now - a game where the players play the monsters (vampires, ghosts, etc) and the DM plays the PCs. I thought it would be a fun twist for Halloween. Not sure of the logistics of it though, as far as how to run it. Would the PCs play the monsters while defending their castle/lair, and the DM play the invading PCs? Or would the players play monsters attacking the PCs in their home town? It could go either way, just not sure which to go with. The former seems a bit better, but it seems odd that the players would be almost pre-staging their attacks and strategy, while the DM would be making it up as he goes along, the way the PC usually do.

One problem I do see is that it would be a lot of work for the DM!

[RPG Dinosaur]

I have never run a game like this myself. The monsters you listed the PC's potentially running are all undead, "vampires, ghosts", and one thing I would say, but probably don't need to, is that to stay within the logic of the game I would limit the monsters that the players might run to those with at least a low intelligence. That would apply to any non-undead as well. That way you don't have the players having say, mindless skeletons and zombies, performing battle tactics that they wouldn't be capable of ordinarily. Maybe this is unnecessary restriction, I don't know your players and maybe they are experienced enough and mature enough to play any monster they way it would behave normally. Even if that's the case, I can't really see the enjoyment of playing a non-intelligent monster, it would be so limiting.
In my opinion, this is really a big topic, players potentially playing monsters. I'm sure I'll (and probably others on the boards) will come up with other points of discussion about this , but the intelligence issue is all I've got for now.

[Halaster-Blackcloak]

That's the biggest issue for me:

Even if that's the case, I can't really see the enjoyment of playing a non-intelligent monster, it would be so limiting.

Kinda hard to enjoy playing a zombie or ghoul I would think. Playing the more powerful undead means a rough time for the DM's PCs. I think it would boil down to the type of game the players want to play. Do they merely want a diversionary Halloween horror romp where their monster characters slay humans, elves, and other assorted PCs, or do they want a challenge from a reverse point of view - i.e. do they want the DM to have the PCs really trying to kill them?

[RPG Dinosaur]

Another issue that has come to me is what if you controlling PC's have a Cleric decide to try and turn a Player freewill Undead. Suppose a turn attempt is successful, without destroying the Undead (T, not D). At that point are you going to assume control of that particular monster(s) to determine where they/it flee?
EDIT, twenty minutes later: On second thought, I think this is probably a non-issue. If the players are controlling the freewill Undead in every other way, why shouldn't they control where a turned Undead flees to, as long as it is out of sight of the Cleric that did it? And if the Players monster is cornered in, the Player just has it follow the guidelines for that situation.

[Halaster-Blackcloak]

I'd consider it a no-issue because I'd handle it similar to a charmed, hypnotized or magic-jarred character, or any other situation in which the DM takes control of a PC.