I think I need to backpedal on that.
Okay, in 95% of cases, grabbing is still a bad option for players. But monsters, on the other hand - they can really get leverage from a good grab attack.
The first encounter in the Well of Demons is the Chamber of the Well. The well in question is 10 feet wide and 30 feet deep and completely dry. It does not contain any demons.
I actually had to stop for a minute, coming back to this encounter. Clearly the well in this room is the eponymous Well of Demons. I'd actually assumed that the Well of Demons was a different, larger hole located in the Proving Grounds. The Proving Grounds hole contains a dragon; I was probably letting my memories of the black dragon Khisanth emerging from the well in the original Dragonlance module colour my thinking.
In any case, while there's no demons (yet), there's no shortage of monsters. The room is home to a pair of cavern chokers, chameleonic ceiling-dwellers notable for their long claw-tipped tentacles. There's also a paralysis-inflicting ghoul, and a phalagar. Phalagars are new to 4th Edition in Thunderspire Labyrinth and are basically burrowing tentacled monstrosities.
This is the sort of oddball monster team-up that 4th Edition loves, and this is an example of it done exceptionally well. Thunderspire suggests the four creatures have by a kind of symbiosis learned to work together to turn the entrance into a kind of specialised killing floor, and indeed that's the experience players will have when they trigger the encounter.
I'd mentioned before that the Well was originally a minotaur monastery. When players first enter the room, a sort of magical recorded message starts up, welcoming "seekers of Baphomet's boundless glory" to the Well and urging them to "prove worthy" of his attention. However, before the message can even complete its cycle, the chokers take advantage of the players' distraction to attack.
The chokers are attached to the ceiling. They use their (reach 2) tentacles to make surprisingly effective grab attacks at the players, which flavour-wise represent the tentacles wrapping around their victim's neck and lifting them, choking, into the air. Victims of a successful grab take a whopping -6 penalty to escape, and the choker can use the hapless hero as a body shield to absorb damage dealt out by the hero's allies.
Meanwhile, the phalagar is burrowing underground towards the players. Concealed beneath the heavy stone floor it's completely impervious to most attacks, only offering a vulnerability when it sends its tentacles to the surface to strike. Like the chokers, it's focused on grabs, and is able to target enemies up to four squares away for this purpose. It also has an awesome rechargeable tentacle flurry which imposes grab (and a big handful of damage) on every target within close burst 2. It's a Large-sized monster, so that's a 6x6 area of effect we're talking about. Creatures grabbed by the Phalagar take ongoing acid damage every turn they remain grabbed.
Anyone who didn't have respect for the grab mechanics is going to learn it very quickly. Players who've been on cruise control through the last few Duergar fights are going to be shocked to find things getting rapidly out of control as they try to deal with this set of very focused enemies.
I love this encounter. I love the way it showcases very different monsters working together. I love the bait-and-switch of the recorded message covering the approach of the monsters. I love the way it makes the grab rules really work, and I love the three-dimensional feeling of chokers from above, phalagar from below and ghoul in the middle. There are some really excellent set-pieces coming up later in the Well but there's a simplicity and elegance to this first offering that holds a real place in my heart.
Dungeon Masters take note: this is how to start a dungeon. Be surprising, be vicious, and be challenging. There's a short series of unexciting gnoll encounters coming up before we get to the Proving Grounds but despite their weak mechanics there's real tension through all of them. And why? Simply because of this first encounter, which has a simple and well-delivered message for players: heads up - shit just got real.