Question: Could you create a random table to generate Mythos-style monsters for The Outer Presence module, kind of like the alien creation tables in Alpha Blue?
Answer: My reservation is that fantasy and sci-fi games expect an endless parade of monsters, from the not-that-realistic to the silly side of gonzo. More serious and real world based settings like The Outer Presence demand a careful eye when it comes to creature creation. Too much randomness and all of a sudden you've got a beast that's part elephant, part bacon with tentacles. That won't elicit dread so much as laughter.
Additionally, those handcrafted creatures should be few and far between or else you may as well be playing a fantasy or sci-fi game.
Having said that, there is a table included in How to Game Master like a Fucking Boss which is for spicing up boring monsters.
Thanks for asking,