I love #12. Organic and creepy. Any way to make it even more creepy/menacing without losing the simplicity? Also, just for readability, can you make the bottom of the "a" have just enough separation on the lower right to make sure people know it's an "a" and not an "o". Good stuff!
14 seems less organic to me, less like a living creature, and more computery. It's gotta be a living creature or organism. To me that means being uneven, slimy, gooey, etc. And it can't be an animal from earth that people will recognize.
I think you nailed it with number 12. It's really simple yet conveys the creepiness. I don't think any of my egg/tentacle ideas are as good. If I was going to comment on your egg #16, I'd say maybe if the egg was above the word "Spawn" and it was hatching downward, and tentacles were coming out and grabbing the word. And perhaps there's an eye peeking out. But I think it might be a waste of your time. #12 rules! Can you bend the lower right of the "a" in #12 just a bit to make sure people with bad sight know it's an "a" and not an "o"?
24 is VERY creative! However, you're going to have a hard time beating 12, which is so clean, cool, yet intriguing. Could you make a duplicate of 12 with the "a" shaped like it is in 17? Or maybe that's the type of tweaks that we do after the contest is over? I don't know. This is my first LogoTournament.