Monstrous Physique I vs. Hit Points

[Reynolds-sama]

Let's say that i'm a 11th level wizard, and i cast Monstrous Physique I...

Do I keep my hit points?
OR
Do I get the final creature's hitpoints (corrected by eventually lowering the COS value reported in the Bestiary)?

[DM_Blake]

You only get what the spell says you get.

You are not turning into the monstrous humanoid. You don't suddenly become the monstrous humanoid. Basically, you are still yourself, but now you're wearing a monster suit. All your ability scores, skills, feats, class levels, etc., all remain the same (although your STR or DEX might get changed slightly), as well as your AC, BAB, CMB, etc. (your AC might change a little bit with size modifiers and natural armor from the spell).

So it's you, in a foam-rubber suit, with tiny modifiers to a few of your numerical statistics.

In short, your HP are unchanged - it's still you in the monster suit.

[Pupsocket]

The rules you are missing are in the Magic chapter, Transmutation school, Polymorph tag.

[Daniel Turner Zen Archer]

If the spell you cast gave you a bonus or penalty to constitution, you'd get the extra health at the moment that you cast the spell.

[DeltaOneG]

Monstrous Physique:

When you cast this spell, you can assume the form of any Small or Medium creature of the monstrous humanoid type. If the form you assume has any of the following abilities, you gain the listed ability: climb 30 feet, fly 30 feet (average maneuverability), swim 30 feet, darkvision 60 feet, low-light vision, and scent. If the form you assume has the aquatic subtype, you gain the aquatic and amphibious subtypes.

Small monstrous humanoid: If the form you take is that of a Small monstrous humanoid, you gain a +2 size bonus to your Dexterity and a +1 natural armor bonus.

Medium monstrous humanoid: If the form you take is that of a Medium monstrous humanoid, you gain a +2 size bonus to your Strength and a +2 natural armor bonus.

You get the listed abilities if you chose a form with that ability.

If you pick a small creature you get +2 dex and +1 NA
If you pick a medium creature you get +2 str and +2 NA

If you're size changes you get the applicable size modifications (ac, to hit, damage dice from weapons)

Nothing changes your HP.

[Reynolds-sama]

Well, what can i say?
Thank you guys :)