Designing a Chapter Closer Fight.

My Gestalt group im running is currently is level 6. We have a #1 Warlock / Warblade. #2 Warblade / Scout / Barb 1. #3 Duskblade / Warblade (I have no idea why they all chose warblade... ) #4 Troll (savage progression) / Barbarian #5 Succubus(Savage Progression) / Bard. And #6 a Psychic Warrior / slew of other classes archer build. Group wise pretty.. weak only 2 "casters" and they aren't amazing casters. Everyone seems to have a thing for melee. (Note 2 of the players are pretty new and had assistance in their builds from other players.)

The upcoming fight is supposed to be a mad scientist sort of guy who's had access to a relic that lets him alter creatures (grafting basically) and I'm trying to figure out exactly how to build this scientist guy and how many minions I should throw for the fight to be decently challenging. I've been trying to avoid save or sucks (Or die) because if everyone rolls like **** the fight could be over and I find it rather anticlimactic. Does anyone have any suggestions? (They're all at full HP from the last fight just before this and the only major cooldowns blown are the Bards Bardic Music attempts, all and both Barbs rages and the 1 Belt of Battle one of them had.)

Minions with grafts that give them multiple attacks and crazy grappling. Give the scientist an alchemical item that when it hits a dude, fort save 20 or a bony knobby tentacle grows out of where and who it hits. The tentacle attacks any thing nearby and has improved grab with a strength of 30. The tentacle tries to pin and hammer whatever it hits. It may tether the PC to another PC, or a PC to a large sized minion. The tentacles don't change target after the first one it grappled is dead (DC 25 performance acting or bluff to trick). The PC can cut the tentacle off for 4d6 damage fort save 10 + damage for half. The tentacles act on pcs turn, PC has choice to go before or after tentacle each turn.

The mad scientist should be the primary enemy, and he should be accompanied by a number (maybe three to five) of his creations. Mad scientist tosses debuffs around and supports his creations, which deal the actual damage. Maybe vary the creations some; you could have a tentacled grappler, a low-mobility acid-spitter (squishy but with high damage), a disruptive flier (maybe it has a tail that it swings beneath it to trip people), and a standard natural-weapons brute.

Make the mad scientist level 7, and the creations CR 4. It'll be a rather tough fight (EL 10), especially since the action economy is mostly even, but it shouldn't be horrible if you don't have the creations focus fire on one party member at a time.

It really depends what style of encounter you want.

Sure conjurations like Cloudkills, Solid Fogs and Evard's Black Tentacles could run amok, and enchantments like Incite Riot/Friend to Foe cause headaches, but for thematic purposes it might be more memorable to go with transmutations.

While the Alienist prestige class works on a different principle, you might want to tweak it to fit your mad scientist.

Keep the focus on the scientist's creations. Shock the PCs with a spell that temporarily merges two animals/monsters into one bizarre but deadly creature...another spell that gives them extra arms or a unicorn horn....make them 50% immune to crits/precision because their anatomy is so foreign...one of the creatures could appear somewhat humanoid and they realise it's a female about his age, maybe his wife??

In short, never have him directly attack the PCs but make sure the strange buffs result in minions that really stretch the PCs capabilities.