Aspects

Aspects are physical descriptive qualities possessed by thulhu and cultists. Aspects are more than just physical (or energy-manifested) literal concepts. They're spiritual resonances. It's something to do with geometry; nobody's really figured it out yet! These are the eight Aspects known to pokéthulhu science (and examples of popular thulhu that have these Aspects):

Decomposing: For dead/undead thulhu, or thulhu that just smell that way. Whip-Poor-Will is a Decomposing thulhu ('cause she's a death spirit).

Fishy: Speaking of smells! Swimmers and clawed beach-scuttlers alike are often Fishy. Dagong is a fishy thulhu.

Fungous: Soft, squishy, yielding and mushy thulhu have this. Fungal Cluster is the most popular example.

Icy: They come from cold planets and can freeze you solid! Pokéthaqua is an icy thulhu.

Luminecent: For thulhu using strange energies. Randy Carter's own cute little Pikathulhu is luminescent.

Non-Euclidean: For thulhu who warp in and out of space and time, or run at right angles to reality. Tindaloo is a non-Euclidean puppy escaped from the Cheap Curry Dimensions.

Squamous: The scaly, the slitery, the ophidian and the reptilian (and those who hang out with them) are squamous, just like Scuttle.

Sticky: The wet, the slimy, the elastic and tentacular are sticky thulhu. Nine-Tentacled Ftaghn isn't just sticky, it's especially sticky.

Every thulhu has two aspects, and a weakness to one (which may be one of its own aspects). Cultists have aspects, too, and are better at training thulhu that share an aspect with them.