Also, the mucous looks like it's coming out its nose, not mouth. 

Looks like "mother's" parents were consuming a little too much whiskey while she was gestating inside a nuclear inferno.  That's probably why she's vomiting.  Her stomach is understandably upset.  

You know...that comment I made in jest now has me thinking....

Mother pukes and it unleashes Bob and weird frog-moth eggs. 

Now we have people puking up strange stuff.  I wonder what's in their vomit?  

It/she doesn't seem to have much in the way of facial features - so the 'stuff' could just be coming out a hole in her head - like Johnny's teddy had...