Wow - tonight's "Ghourmand Vale" adventure was a new low. The plot was simple enough: we arrived in Greyhawk City, turned over the rescued frost barbarians who had been captured by orcs in the previous adventure, the PCs were each given an amulet valued at 350 gp that showed them as "friends of the frost barbarians," and we spent the night at my PC's brother Atherton's villa. The next day we did some shopping, to include buying fancy clothes for a dinner party Atherton was holding the following day, with guests including my PC's parents. (I had been kicked out of the noble family when my sorcerous powers started manifesting, as my father assumed I'd been trafficking with fiends to gain these spellcasting powers.) While waiting for my mother's brother Conrad to show, a ransom demand was delivered: they wanted Atherton to bring the Pastlethwaite diamonds to a warehouse in exchange for Conrad's life.
Atherton, suspecting this was an attempt upon his life (and passing on his suspicions that Uncle Conrad was in on the deal), had our PCs go in his stead to deliver the ransom. So we showed up, I had my grackle familiar do a recon flight around the warehouse (3 doors, no windows, no holes in the roof, nobody watching the area), and we set up an ambush: the elf archer was on the roof, aiming down at the door I'd be entering (I was going to pretend I was my brother Atherton), the halfling rogue was waiting to stab at anyone coming out the door from one side and the half-elf paladin was doing the same on the other side, and my grackle was perched on the roof keeping a watch out.
I pounded on the door, announced my presence, and demanded to see Conrad. A voice from inside told me to come in. I kicked in the doors, saw two shadowy figures in cloaks, and demanded Conrad be brought forth at once, for I had the ransom. The voice told me to step into the pitch-black warehouse. Not being suicidal, I refused, made a big stink about having my aristocratic time wasted, and stormed off (hoping at least we could get a flunky to come outside and spring our ambush).
Nope. The DM absolutely insisted I enter the pitch black warehouse. When I refused, he recanted and decided there were lit torches inside the warehouse after all, but I still demanded the kidnapper bring forth Conrad before I paid over any ransom. Finally, he had the babau demon (the only actual enemy in the whole adventure - the two "cloaked figures" and four more just like them inside the warehouse were all dead, each missing a different body part, and were propped in place - apparently somebody's been making a flesh golem) teleport just outside the gate in the fence where I was about to exit, so he could get in a readied attack when I opened the gate...with the fence retroactively being suddenly 8 feet tall to explain why my familiar (who was aimed in my direction atop a 20-foot-tall roof) didn't see anything and so didn't warn me. The babau clawed me down from 27 hp to 9 hp (it was a successful crit), and then the other PCs got in on the fight, dealing it a bunch of damage (especially the paladin, whose smite evil attacks quickly brought it down to single digits). It teleported back inside the warehouse, we went inside to follow, it cast darkness around it, but that didn't stop the archer from continuing to hit it with cold iron arrows. Finally, the halfling was going to hit the babau with a sling stone that was really a small boulder under the effect of one of my shrink item spells, when the DM informed me it was too dark for me to see what the halfling was doing so I couldn't call out the command word that would restore the boulder to its full size in mid-flight. Then the archer suggested the halfling shoot it at the ceiling directly above the babau, since impact would also restore the boulder to its full size, and gravity would then drop it on the babau's head. The DM then decided that a small boulder wouldn't deal any damage simply by falling onto a foe unless it fell at least 40 feet (the ceiling was only 20 feet tall)...despite rulings in our previous 16 adventures that having a fist-sized rock dropped from my unseen servant merely releasing it while holding it over a foe's head dealt 1d3 points of damage. We pointed out we were aware the babau had DR 10 and thus we'd need to deal 11 or 12 points of damage on 2d6 (the amount we had previously agreed upon earlier that a restored-to-full-size-before-impact boulder would deal) to deal any damage at all to the babau, but he wouldn't even allow us to try.
Finally, the archer made the whole point moot by killing the babau with another cold iron arrow when it was her turn. But we were very concerned that the DM had apparently suddenly decided none of our plans would ever be allowed to work, even if it meant going 180 degrees from previously-established rules of the game.
And, what made this particularly galling: in the campaign I ran prior to my current campaign, I had designed a slingshot of rock shrinking specifically for the DM's character (he was a player in that campaign), since he ran a wizard with an earth elemental familiar. That weapon allowed a "shrunken" piece of stone to be restored to its original size upon impact, dealing damage as if it had been its full size all along. And we had jointly come up with all kinds of ideas on creative uses for the shrink item spell at work this past week, so I was confused as to the sudden reversal of policy.
Fortunately, we discussed the problems with the night's session at work this morning (he was well aware none of his four players was very happy with how he had handled the session, including his wife), and it doesn't seem to have been an intentional display of adversarial DMing; he was just a little unsure of things and started making snap decisions on the fly. (For example, he said he couldn't find in his notes where babaus had darkvision so assumed he must have made an incorrect assumption, resulting in him "remedying" the situation in a very suspicious-looking way by retroactively adding torches in the warehouse interior.)
In any case, next week's session is almost guaranteed to be better than this one, but I'm willing to chock it up to inexperience rather than an adversarial attitude.
Johnathan