Step right on down and make the purchase of a lifetime! It's our very own patented Tex in a Bottle™! For 10 easy payments of 300 bits, and of course your sanity, it can be all yours! How do you use it? Just caress the bottle then set it down and you have summoned your very own Tex™! Remember, no refunds! Oh and no returns!

Sounds like the purchase of a lifetime, huh? Well for some it's not, especially if you didn't buy it.
Sunset Shimmer did not buy a Tex in a Bottle™, no, she got a free item that she doesn't want. Kinda like a kid but not.
It is now up to Sunset Shimmer to figure out who gave her this "lovely" free item, and figure out how to get Tex back into the bottle. If life wasn't hard enough without Tex, it's like having a nice bike ride through Tartarus while on fire, and having to deal with a child that wants to go to Didney Lan but you have no money so they are there riding a bike with you in scenic Tartarus.