Improving Monsters and Polymorph

[arcseed]

I can't find anything in the rules to prevent polymorphing into a monster with a HD increase that causes a size increase-- and gaining the benefits of increased STR and CON, as well as size-increased natural weapons and improved natural armor. (and the greater size penalty to ac and attack, of course) Is this really kosher?

I have my eye on the 11 HD gargantuan wyvern-- STR 35, poison DC increased to 21 from the increased con, and attacks ranging from 2d6+12 to 4d8+12. I'm unclear as to how many attacks are included in the wyvern's full attack however-- the description says the talons can only be used for the flyby attack, yet are included in the stat block in the full attack. As the wyvern has poor maneuverability, it won't ever get the opportunity to full attack while flying.

 

[Sekhmet]

I can't find anything in the rules to prevent polymorphing into a monster with a HD increase that causes a size increase-- and gaining the benefits of increased STR and CON, as well as size-increased natural weapons and improved natural armor. (and the greater size penalty to ac and attack, of course) Is this really kosher?

I have my eye on the 11 HD gargantuan wyvern-- STR 35, poison DC increased to 21 from the increased con, and attacks ranging from 2d6+12 to 4d8+12. I'm unclear as to how many attacks are included in the wyvern's full attack however-- the description says the talons can only be used for the flyby attack, yet are included in the stat block in the full attack. As the wyvern has poor maneuverability, it won't ever get the opportunity to full attack while flying.

The assumed form can’t have more Hit Dice than your caster level (or the subject’s HD, whichever is lower), to a maximum of 15 HD at 15th level.

functions like Alter Self

You acquire the physical qualities of the new form while retaining your own mind. Physical qualities include natural size

I think that about covers it. If you have the requisite caster level, an advanced 12HD Wyvern is fine.

Base attack would improve to 12 (1 per HD), giving him three attacks at +12/+7/+2. A full attack would consist of either a Sting, Bite, and Wing; a Sting and two Wings, or a Bite and two Wings.
Claws may only be used during a Flyby Attack action, and you cannot Full Attack as a Flyby Attack with or without the feat.
The Flyby Attack feat would allow you to use two Claw attacks.

 

[arcseed]

Base attack would improve to 12 (1 per HD), giving him three attacks at +12/+7/+2. A full attack would consist of either a Sting, Bite, and Wing; a Sting and two Wings, or a Bite and two Wings.
Claws may only be used during a Flyby Attack action, and you cannot Full Attack as a Flyby Attack with or without the feat.
The Flyby Attack feat would allow you to use two Claw attacks.

Okay, that's not right. The wyvern's attacks are a natural attack routine, not iterative attacks. And, since we're talking about polymorph, they're based on the character's BAB, not the wyvern's HD. The full attack is a sting, at BAB + STR - size, plus a bite, two wings, and possibly two talons, all at BAB + STR - size -2 (for the racial bonus feat multiattack, otherwise it would be -5).

Also, flyby attack should allow only one talon attack, despite the description using the plural. I suspect something wrong with the wyvern entry in the SRD, but don't know how to interpret it.

 

[Iku Rex]

Can you become advanced versions of creatures with
polymorph* (PH 263), or just the most basic as presented in
the MM?
The rules don’t explicitly prevent this, but for speed of play
(and reasons of sanity) it’s entirely reasonable for a DM to
disallow any forms other than those detailed in the MM (or
other allowed volumes of monsters). If the DM chooses to
allow advanced creatures, the player must supply full statistics
for the advanced version before play begins. Remember that
the Hit Die limit for the various polymorph spells still applies
(a 7th-level wizard can’t use polymorph to assume the form of
a 10-HD advanced sahuagin).
*The question and answer uses “polymorph” to refer
specifically to spells that rely on the polymorph or alter self
spell to adjudicate their effect (including alter self, polymorph,
polymorph any object, and shapechange), psionic powers based
on the metamorphosis power (including metamorphosis and
greater metamorphosis), and any other effect based on either of
these lists.

(Also, IMO "the new form must be within one size category of your normal size", but I believe WotC employees have said otherwise.)

 

[arcseed]

Thanks. That was what I was looking for. I guess I'd probably not allow it as DM, unless it was specifically a high-powered anything-goes game, and I'd not want to use it as a player in a regular power level game, but it's nice to get the official word.