I really like this question. :D I’m happy you asked. I have a few to share actually.

http://fuckyeahnebulas.tumblr.com/post/479630604/veil-nebula#notes

This one is just strange to me, mainly because I can kinda see a skull like figure. :o

http://fuckyeahnebulas.tumblr.com/post/413834274/keyhole-nebula#notes

This one kinda looks like its flipping me off. I found this to be strange as well lol

http://fuckyeahnebulas.tumblr.com/post/4566107239/hourglass-nebula

This last one just always creeped me out D: The damn eye figure in the center haunts me. 

Thanks for asking ;D