Now I'm starting to think that it really could be slime mold! My first pile of stuff didn't look like the pictures, but I found more in another area today. This time, it looks like one of the dogs had diarrhea, which is super gross! This pile of stuff is also behind the rabbit fence, where the dogs can't get into, so I know it's not them! Maybe I've got a sick pterodactyl in the area?