How does this scenario involving the Polymorph and Alter Self spells play out?

Question

We had an interesting scenario pop up at our table. A dwarven runesmith (Races of Stone p.118) with caster level 9, getting ready for a big battle, did the following:

1. He set all his equipment out on the ground so nothing would be eaten by polymorph
2. He cast Polymorph and turned into a Behir
3. He cast Girralon's Blessing (Spell Compendium p.106) to gain a pair of arms
4. He cast Fearsome Grapple (Spell Compendium p.90) to gain 2 pairs of tentacles
5. He cast Fuse Arms (Spell Compendium p.100) for +20 untyped str from the Behir's 2 extra pairs of claws + everything gained from his spells
6. He then cast Alter Self and turned back into a dwarf
7. He put on all his armor and cast Fist of Stone (Spell Compendium p.94) for a +6 enhancement bonus to strength
8. He cast Enlarge Person on himself to become large and get +2 size bonus to strength

All told, he claimed to be a Large Dwarf with 54 strength, 11 dexterity, and 21 constitution.

To what level does this work?

The argument was that Alter Self transforms you based on your "normal form" which is a dwarf (this is based on the assumption that "normal form" is what would be seen if viewed with a True Seeing spell), but it explicitly doesn't affect any of your ability scores, which are obscenely high from the Polymorph. And since he assumed the form of that creature (a humanoid dwarf), it changed his type back from magical beast so he could still cast Enlarge Person. Is he correct?

Answer 1

The plan in steps

1. If all this doffing and donning is cutting into the duration of those buff spells, a ring of arming (Magic Item Compendium 122) (5,000 gp; 0 lbs.) and a druid's satchel (Dungeon #92 103) (3,000 gp; 5 lbs.) may be wise investments.
2. A behir (Monster Manual 25) possesses a size category of Huge while a dwarf possesses a size category of Medium. The 4th-level Sor/Wiz spell polymorph [trans] (Player's Handbook 262) inherits everything but its exceptions from the 2nd-level Sor/Wiz spell alter self [trans] (PH 197). The spell alter self, in part, says, "The new form [that's assumed using the spell alter self] must be within one size category of your normal size." The spell polymorph, in part, says, "You can't cause the subject [of the spell polymorph] to assume a form smaller than fine…." While many read polymorph as removing the size limits of alter self, the two are neither contradictory nor incompatible. Ask the DM if a Medium creature can use the spell polymorph to assume Huge or bigger or Tiny or littler forms. (See also this question.)
3. The 3rd-level Sor/Wiz spell girallon's blessing [trans] (Spell Compendium 106) possesses a duration of 10 min./level.
4. The 2nd-level Sor/Wiz spell fearsome grapple [trans] (SpC 90) has a duration of 1 round/level.
5. The 2nd-level Sor/Wiz spell fuse arms [trans] (SpC 100) has a duration of 10 min./level. Assuming the DM allows all these limbs to fuse, the weak link here is the spell fearsome grapple. While the creature should be fine—spells usually don't care if their targets becomes invalid after they're cast—, the DM may look askance at the dude after 1 min. when he still possesses an increased Strength score from the spell fuse arms yet some of the arms that the spell fused have disappeared!

6. The Player's Handbook on One Effect Makes Another Irrelevant includes the following situation:

   Sometimes, one spell can render a later spell irrelevant. For example, if a wizard is using a shapechange spell to take the shape of an eagle, a polymorph spell could change her into a goldfish. The shapechange spell is not negated, however, and since the polymorph spell has no effect on the recipient’s special abilities, the wizard could use the shapechange effect to take any form the spell allows whenever she desires. (172)

   While certainly this could be even clearer, at least one reading of this section is that the effects of form changing aren't cumulative. That is, changing form again renders irrelevant the forms into which the creature has changed previously, making it so form-changing effects are always based on the creature's natural or original form—pick your favorite synonym—rather than on any assumed form. Hence it's not just a matter of lawyering how the spells alter self and polymorph work in conjunction but a matter of determining how the game is supposed to work, and, ultimately, that's what DMs are for.

   So it's possible and reasonable for a DM to rule that when the caster uses a polymorph spell to assume behir form then uses alter self to assume dwarf form, everything about the behir form is rendered moot by the dwarf form. The creature isn't a dwarf that's become a behir then a behir that's become a dwarf; the creature is a dwarf who used form-changing magic to assume behir form who then suppressed that behir form—therefore all that the behir form entails—by using form-changing magic again to assume dwarf form. (Also see this question.) If the DM rules this way, the plan pretty much falls apart completely.

7. Just to be clear, the 1st-level Sor/Wiz spell fist of stone [trans] (SpC 94)—that also has a duration of 1 min.—, in part, says, "You transform one of your hands into a mighty fist of living stone, gaining a +6 enhancement bonus to Strength for the purposes of attack rolls, grapple checks, or breaking and crushing items" (94). However, the enhancement bonus to Strength does not apply to the subject's damage rolls except with regard to the natural slam attack the spell provides. I mean, it's still a good spell, but it's not a replacement for a normal +6 enhancement bonus. (The spell's enhancement bonus to Strength also doesn't lend itself to increased carrying capacity or aid with Strength-based skill checks, for instance.)

8. The spell polymorph changes the creature's type and the spell alter self doesn't, so if the DM allows the two spells to combine for a cumulative effect, the dwarf-behir-dwarf's creature type is magical beast and the 1st-level Sor/Wiz spell enlarge person [trans] (PH 226–7) fails outright.

   Alternatively, if the alter self spell suppresses the effects of the polymorph spell, then the enlarge person spell functions normally, but ending or suppressing the alter self spell, according to one designer, won't yield a Gargantuan behir (i.e. one that's affected by the enlarge person spell). Dungeons & Dragons, Third Edition co-designer and Monster Manual author Skip Williams in his Rules of the Game Web column "Polymorphing Revisited (Part Four)" says

   Effects that work some sort of physical change on the recipient fall under the rules for effects that render each other irrelevant [q.v. #6.]. For example, spells such as fins to feet and girallon's blessing from the Spell Compendium both transform the recipient physically (the former turns a creature's swimming fins or tail into motive legs useful on land, the latter spell causes the recipient to literally grow an extra set of arms). Since a creature gains the assumed form's body layout and limbs upon changing, the change in form makes either spell irrelevant. For example, if a creature using either spell assumes the form of a horse through alternate form, it becomes a typical horse, with four legs and four feet with hooves. If the creature later reverts to its original form, either spell still applies to the creature, provided the spell's duration hasn't run out.

   By extension then, when a creature uses form changing magic to assume a new form that new form's size is the same as that of a typical creature (although it could be modified later). In other words, just because jumbo dwarf becomes a behir doesn't mean jumbo dwarf becomes a jumbo behir!

Answer 2

"The argument was that Alter Self transforms you based on your "normal form" which is a dwarf (this is based on the assumption that "normal form" is what would be seen if viewed with a True Seeing spell), but it explicitly doesn't affect any of your ability scores, which are obscenely high from the Polymorph. And since he assumed the form of that creature (a humanoid dwarf), it changed his type back from magical beast so he could still cast Enlarge Person. Is he correct?"

No, this interaction between Polymorph, Alter Self, and Enlarge Person does not quite work, though the spell chain you describe would nominally work through step (7).

Even if we grant that the polymorphed Dwarven Runesmith is a valid target for Alter Self, that Dwarven Runesmith would still retain the type and subtype of its most recent Polymorph, in this case retaining the magical beast type of the behir and thus being an ineligible target for Enlarge Person.

Alter Self offers has the following proscription:

Your creature type and subtype (if any) remain the same regardless of your new form.

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With regard to whether or not a creature who has used Polymorph can legally target themselves with Alter Self, it seems like a DM judgment call. The plainest reading of the two spells does not seem to preclude their use together - nothing in Alter Self requires the target to already be of its normal form, just that the spell grants the physical form of a creature within the same type as the creature's "normal form." This requires some discernment of what a creature's "normal form" is, which is certainly a decision for a DM to make in these kinds of interesting edge cases.

(n.b. The limitations of Alter Self - specific to this case, the loss of Special Qualities and the hit dice cap are most germane. This Dwarven Runesmith-turned-behir-turned-Dwarf would lose the SQ slot of the behir, thus losing the immunity to trip attacks, darkvision 60 ft., immunity to electricity, low-light vision, and scent. This Dwarf would also be limited to assuming forms of humanoids with no more than 5HD. A particularly parsimonious DM might rule that using Alter Self in this manner results in assuming the form of the typical Monster Manual Dwarf, which is a creature of 1HD. Spells like Sleep and Color Spray, which have effects determined by the hit dice of their subject, become much more dangerous to the PC in such a situation.)