Need help finding monsters with battlefield controlling abilities (3.5)

[jcsw]

Well, this is an amusing request:

I've got a boss encounter, Wizard 5/War Weaver 5/Spellguard of Silverymoon 5/Legacy Champion 5. Can cast personal spells of up to level 9 through the weave. Also found a way to make all spells heal, so yes, I can cast time stop through the weave.

She's surrounded by high HP underlings...

What this means? Mass Shapechange.

But obviously I could have mass beholders shooting eye beams at the PCs, but this isn't fun. So I decided that each round the underlings should change form to something new, countering the PCs previous strategies, forcing them to change strategies each round.

And so, the first round involves a shared time stop where all the underlings massively alter the battlefield.

Which brings me to the question: There are a number of monsters with battlefield altering abilities. The top in my mind is the Magmacore Golem, which can create pools of lava on the field. What others out there exist?

[Olo Demonsbane]

Anything with a wall SLA. A sculpted Wall of Stone is FUN!

EDIT: You can use it to create 3D mazes if you have enough time/creatures (I forget what the sculpted area can be for a cube). Then you all turn into tanar'ri and summon an army of demons to hunt the players down! You can wear anyone down after enough mariliths.

[Telonius]

Are you just looking for things that can literally alter the battlefield (as in, changing where rough terrain is, making a hill, etc), or would figuratively altering the battlefield (summoning, Fear aura, Blasphemy, etc) work as well?

[jcsw]

Well, anything which can be done within a time stop, really, but note that the PCs are actually ECL 22.

Also, avoid spamming saves at PCs, that's just no fun. (If I wanted to do *that*, they'd all shapechange into beholders...)

(Yeah I think the cheese factor is enough to make the ECL 20 encounter dangerous enough. :P)