Is there anything about the mythic subtype that removes creatures from being valid shapes for polymorph spells?
I'm working on making a list of valid shapes for Brown Fur Transmuter to apply to the party beatsticks with Monstrous Physique II, and have just noticed Grendel. No special abilities to speak of, but a 4d8 bite and two 3d10 claws is a pretty substantial step up from most of the available monstrous humanoids.
Grendel is a unique creature - doesn't that make him not a valid shape?
I had not actually considered that. That certainly seems like a valid line of reasoning.
At least that restricts me to Fomorian Queens for ridiculous claw damage. And those have an actual drawback with that 5' movement speed.
Unless otherwise noted, polymorph spells cannot be used to change into specific individuals.
Right - so unless there's a species of Grendels (he did have an equally monstrous mother, but he was some sort of half-breed with a demon, if memory serves - not an actual species) - you can't be 'a Grendel'.