Advice on 16th level Cat-shaped Eidolon needed

[nightflier]

Here's the deal: I need to create a 16th level summoner NPC. For story reasons, Eidolon needs to be cat-shaped and to have six legs, instead of usual four. I have never played a summoner, or DMed a summoner NPC, so I really need a hand with this.

I do need a detailed Eidolon build. Summoner by himself is not really important.

[Cheapy]

How badly do you want him to kill the party?

Pounce, six legs (take limbs three times), claws, skill focus acrobatics, skill focus stealth, climb speed, maybe energy attack cold.

[nightflier]

He needs to help the party, in fact :)

[David knott 242]

One problem you need to look out for is the limit on natural attacks. At 16th level, that limit is 6 -- so the obvious way to distribute them would be as three pairs of legs each with claws, right?

Not so fast. First off, you need to pick a base form for your eidolon. If you take quadruped, you get Bite for free -- and that only leaves you five attacks, which means that you cannot attack with all of your claws.

If you take biped, you start off with two legs, two arms, and two claws for your free evolutions. So then you buy a second pair of legs and two more pairs of claws to give you your six attacks. Don't worry too much about the fact that you now have a creature with a centaur-like form -- you can simply have the eidolon prefer to go around on all fours (okay, make that all sixes) even though it is perfectly capable of rearing up on its four hind legs and using its frontmost pair of "legs" as arms if the situation warrants it.

With the basics taken care of, I would then take evolutions and/or feats to boost the damage on those attacks -- since they are all identical claw attacks, you get easily boost the damage and other combat stats pretty high.

And you have just gotten started -- I am sure that you still have plenty of evolution points left over.

Finally, think of some fluff ideas -- what sorts of things do you want the eidolon to be able to do? How big do you want to make it? At level 16, you can make it anywhere from Small to Huge. Huge would be best for a literal combat monster, but maybe you are picturing something smaller.