Exactly how big are Eidolons anyway?

[sunbeam]

I'm asking this because I am thinking about making a synthesist summoner character who will as closely as possible emulate being or becoming a noble salamander.

But what puzzles me are the exact dimensions of one.

Okay, assuming you started at level 1 as a medium size serpentine form, you get reach with the bite attack. So what does this mean? Your body is roughly 10 feet long? I really intend to see if I can mod this thing such to have a form like the salamander or a Yuan-Ti Abomination, with no bite attack.

But what would the actual physical length be?

Then you get to the point where you can take the large evolution which reads:

"An eidolon grows in size, becoming Large. The eidolon gains a +8 bonus to Strength, a +4 bonus to Constitution, and a +2 bonus to its natural armor. It takes a –2 penalty to its Dexterity. This size change also gives the creature a –1 size penalty to its AC and on attack rolls, a +1 bonus to its CMB and CMD, a –2 penalty on Fly skill checks, and a –4 penalty on Stealth skill checks. If the eidolon has the biped base form, it also gains 10-foot reach. Any reach evolutions the eidolon possesses are added to this total. The eidolon must be Medium to take this evolution. The summoner must be at least 8th level before selecting this evolution.

If 6 additional evolution points are spent, the eidolon instead becomes Huge. The eidolon gains a +16 bonus to Strength, a +8 bonus to Constitution, and a +5 bonus to its natural armor. It takes a –4 penalty to its Dexterity. This size change also give the creature a –2 size penalty to its AC and attack rolls, a +2 bonus to its CMB and CMD, 10-foot reach, a –4 penalty on Fly skill checks, and a –8 penalty on Stealth skill checks. If the eidolon has the biped base form, its reach increases to 15 feet (10 feet for all other base forms). Any reach evolutions the eidolon possesses are added to this total. These bonuses and penalties replace, and do not stack with, those gained from becoming Large. The summoner must be at least 13th level before selecting this option.

The ability increase evolution costs twice as much (4 evolution points) when adding to the Strength or Constitution scores of a Large or Huge eidolon."

This is kind of wonky. You get some of the benefits of being large, but you don't get reach unless you have a bipedal form.

So .... what would be the physical dimensions of a large, serpentine eidolon? And more specifically, what kind of spaces could it fit into, like passages and such?

Really I would be better off taking the bipedal form, adding a tail, and pretending I didn't have legs. But by RAW, I would never have a constrict attack, because you need to have a serpentine form for that.

But can anyone tell me the dimensions of this thing? What is a large serpentine eidolon? Something roughly human size in width, and 15 feet long? What are we talking about here?

[Kerney]

It is whatever you as a player says it is. If you say a large eidolon is 15 ft long and human shape so it is.

[lemeres]

Well, you could always go with the Space, Reach, & Threatened Area Templates. They give the typical limits for height, area, and weight for each size category (use the long template for serpentine creatures large size or bigger though)

[sunbeam]

Thanks that is probably as good as I'm going to get. Still really doesn't tell me much about what size space you can fit through, tunnel wise and such.

[lemeres]

Hmmm...Ah! Just look up Squeezing. Basically, you can get up to half your normal width, and the area you take up (2x2 for large) is cut in half (2x1 for large).

Justifications for this can be further found in Escape Artist, where you can get into a tight space that you can fit your head into. Just say "He has a big head". As long as the head is as wide as a human torso, then sure, fine. It is as wide as the square a medium character takes up.

I also know that the entire length will of the serpent will not really fit into the 2 squares, but lets just say that the main mass with all the important organ-y bits are in there, and any remainder is just tail dragging behind.

[sunbeam]

Thanks a lot, I never would have thought to look up squeezing.

Basically I need a 5' passage to go through if I take the large evolution.

I may be able to go through something smaller (guess "head size" is just something that will have to be debated. 2.5' diameter for example seems too big even for large size), but since I intend to have arms (and shoulders) it will be more complicated.

I am also kind of assuming that a serpentine body can at least "compress" and extend, so to match head size, for a time at least. I really imagine the bulk of the body being wider than my head, except at the very tail end.