Okay so, Aelzen's supposed to be some sorta outer-demi-god type thing? I don't think this is what his 'actual' body looks like, I reckon that's a non-euclidian mass of weirdness in some other dimension in space or something, but he projects an 'avatar' body on Earth so he can hang out with people and just y'know, have a social life. It's lonely out in space, there's not much to do.

Since this body's one that he's essentially conjured up, it's fully capable of shapeshifting to look like whatever, but 'solid chunk of space' cthulmanoid is his default.