Something out a children's nightmare? Naah. It's something from everybody's nightmare *crazyface* 

Plus, I had to find some source of the acid Nishino wants to use for her acidic bombs :P

Also:
"Tartaric" is a type of acid that you find in bananas and stuff like that. It's a million times weaker than the acid the creature uses, but it sounds like "Tartarus", and it just fits with a cat-sized, eight legged freak creature that eats you alive xD