Combat Maneuver Immune Boss?

[Skystriderfurry]

So I was recently playing #45: Delirium's Tangle on 1-2 tier and we were on the last boss, I did a few Summon Natures Ally (I'm a druid) and brought out several Stirge's on the bosses space which grappled and began doing con damage like they should.

Spoiler:

After the 2nd cast of Stirge's giving me a total of 3, the GM informed me that the boss in question actually has some sort of total immunity to Combat Maneuver's and therefore could not be grappled by my Stirges and therefore took no Con Damage whatsoever leaving me with wasted spells and 3 stirges sitting there doing nothing at all.

Now im still fairly newish to PFS and I just slid with it as I didn't wish to make a scene at the table by calling out the GM on what I suspected was a load of bull.

Can Anyone who has run this scenario or knows this scenario tell me what it was that gives that last boss combat maneuver immunity or if that GM was screwing me over on a perfectly legitimate strategy as a Druid.

[Cellion]

He's immune to combat maneuvers that would move him or knock him prone, but grapples should be OK. The DM may have misread the ability (its honestly worded in a slightly confusing way) as a total immunity to combat maneuvers. The Big Bad has:

Spoilers for Delirium's Tangle:

Delirium's Tangle wrote:

Site Bound (Su) Abysiel is bound in place by sturdy chains and ancient magic. His speed is 0 ft. and he is incapable of any movement. He is immune to all combat maneuvers or any other ability or spell that could move him or knock him prone. Abysiel is always considered flat-footed, even when aware of attacks. The process that bound him to the Tangle also granted Abysiel a +4 enhancement bonus to Constitution and infused him with the light fortification armor quality.

[Link2000]

It does say in the scenario that he is:

Spoiler:

He is immune to all combat maneuvers or any other ability or spell that could move him or knock him prone.

Even though I read that as immunity to some of the combat maneuvers, I can also see it being easily mistaken as the way your GM handled it. Sorry that you got "knee-capped" on this one, but hopefully the rest of your experience was good.

EDIT: Ninja'd

[_Ozy_]

Stirges don't grapple, they 'attach', which means they get the grappled condition but their enemy does not. The wording is a bit confusing in the special ability listed under the monster, here it is from the universal monster rules:

Quote:

Attach (Ex)

The creature automatically latches onto its target when it successfully makes the listed attack. The creature is considered grappling, but the target is not. The target can attack or grapple the creature as normal, or break the attach with a successful grapple or Escape Artist check. Most creatures with this ability have a racial bonus to maintain a grapple (listed in its CMB entry).

[Firebug]

As a slight aside then, could a stirge attach to someone with Freedom of Movement? Since its not actually restricting the movement of the target I would lean toward yes.