TotB Boss fight (spoilers if that matters)

[twicemartyred]

Hey guys, just wondered if we've missed something for a situation that came up in the boss fight of TotB. So. One thing we DID miss was any indication that the Beast was the way you were SUPPOSED to fight the abomination. Although the description of the area was spread over two sessions so wasn't fresh in our mind when it came time to act. Here's what ensued:

Cast: Tank: Warpriest / Cleric of Erastul. ME: Magus/Rogue, Newb: Ranger/Sorc (yeah, gestalt with only three players. Not terribly optimized).

Tank: goes first cause that's what tanks do.
Opens the trap door, ties a rope to the handle.
Uses torch to burn web away from the trap door.
Rest of us: Mill around below wondering what's taking so long. He won't move his plate-mail clad posterior to let us in.
Aberration: Comes downhill like an avalanche.
Tank: Nopes out by jumping down the trap door hole, and pulling the rope to close it. Uses domain power Growth to become enlarged.
Aberration: Catches him with a nifty claw and grapple, in midair. *Tries to pull him through the hole but he's too big*
Group: *Tries hard to find a rule that will explain how to resolve the situation*

One thought I had was that the grapple fails because he can't pull the target into an adjacent square.
Otherwise our ideas ranged from 'can't pull me through, can't get your other claw in here to attack through that relatively tiny hole' to 'if he inflicts N damage with a grapple while trying to pull you in, you crunch and pulp and squeeze through the hole the hard way'.

Wanted to get some feedback on how it should have gone.

[archmagi1]

I've had two groups go through this fight. One was super optimized and was a few lucky rolls from a TPK. The other was about an average power party, and they knocked it out of the webs at the ceiling and 1-rounded it before it could act.

There is no real hint that they should use the Bondslave Thrall at all.

As for the grapple, how I would resolve it is two checks. 1 CMB for the grapple, and they're held below the hatch, immobile, w/ the grapple penalties but w/o Constrict since its on the other side of the hatch. This lets the other players spend their round aiding another to try to get him out of its grip. Next round comes, I would allow the Promethean to make a reposition CMB w/o an AOO to pull the tank through the gap. If it succeeds, it pulls the embiggened PC through the gap, (dealing the constrict damage from last round as it forces him through the hole), and then transfers him to a tentacle as a move action.