Answer:
I only exist when you are here. Where you never were I can never be.
I come without being fetched at night hides away as soon as daylight strikes. Although I may look small I am much mightier than what you can imagine.
Pronounced as one letter but written with three always in evil never in good and always in zebra never in animal. What is it?
I am not a toy though many use me for pleasure. I have a butt but I cannot poo.
I am black and white and full of fuzz
No matter how little or how much you use me, you change me every month.