Is the special attack granted by Righteous Might a Strike?

Question

Casting Righteous Might gives the caster a special attack:

A special attack with a righteous armament version of your favored weapon, which is the only attack you can use. Your attack modifier with the special weapon is +21, and your damage bonus is +8 (or +6 for a ranged attack). If your attack modifier with your deity's favored weapon is higher, you can use it instead. You deal three of your weapon's normal damage dice, or three damage dice of one size larger if your weapon is a simple weapon with a d4 or d6 damage die. The weapon has one of the following properties that matches your deity's alignment: anarchic, axiomatic, holy, unholy. If your deity is true neutral, you instead deal an extra 1d6 precision damage.

The Attack Roll rules seem to make a difference between Strikes and special attacks:

The multiple attack penalty (detailed on page 446) applies to each attack after the first, whether those attacks are Strikes, special attacks like the Grapple action of the Athletics skill, or spell attack rolls.

It not being a Strike would seem to imply that:

• You can't use it with Power Attack
• It does not deal double damage on a critical hit

Is the special attack granted by Righteous Might a Strike?

Answer 1

It's an attack with a weapon, so you can use a Strike action.

Righteous Might has particularly confusing wording with its attack. Of the battle form spells I looked at, it's the only one that includes "special." Spells like Animal Form and Dragon Form specify an unarmed attack, while Avatar unhelpfully says "one or more attacks" with no further specificity.

Especially with regards to battle forms, the words attack and Strike are often used interchangeably. The polymorph trait rules refer to these as "Strikes granted by a polymorph effect" when specifying that they are magical, which I think is the clearest indicator of how to handle these attacks.

Looking at Righteous Might's rules text specifically, what's special about the attack appears to be that it is made with a version of your deity's favored weapon. Unlike the typical unarmed attacks of battle forms, as a weapon, it has its regular weapon traits on top of the benefits of Righteous Might. Otherwise, I'm not sure why the word "special" is in the text.

TL;DR, and to answer the specific questions:

Yes, you would use the Strike action for this attack, so its damage would be doubled on a critical success. You can use Power Attack or any other feat that involves making a Strike while in this form as long as they meet the restrictions of the Polymorph trait.