That's actually a really nicely designed costume, like a wonderful alternative to her original stage gear ;3; really adore the creativity there!
Twilight: What the...? I never bought any dress from that place and..... HOW MANY?!?! SPIKE!!!!
Spike: Woah! What's the matter Twi? And where are you going?
Twilight: Take care the house while I'm gone. I need to have as serious discussion with a certain "magical" pony, right now!
and now Trixie must pay the bill.
and she can't make it disappear.
or pull gold out of her hat.
I don't see it. She seems to be acting normally to me.