Birthday Party Planning for a 4 Year Old

My daughter wants a magic groovy shirt princess party for her 4th birthday...

ME: What do you mean "a shirt party"?
HER: Oh, you know, I'm going to give all my friends shirts.
ME: What kind of shirts?
HER: Just shirts.
...
ME: So, about this shirt party, what if you and your friends decorated shirts?
HER: No.
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ME: I've been thinking about your shirt party, and I really think that instead of just giving your friends shirts, you all can decorate the shirts. Doesn't that sound like a good idea?
HER: No.
ME: Well, yeah, I think it does.
HER: Well, okay.
...
HER: I'll give everyone shirts, and then we'll break the piñata!
ME: What does this piñata look like?
HER: A shirt.
...
ME: (Google Search: shirt piñata)
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ME: The only shirt piñatas I can find are Hawaiian shirt pinatas.
HER: No.
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HER: I want a magic shirt party.
ME: Magic shirts?
HER: Yeah, you know, like the Great Grinaldi. You know, from Odd Squad.
ME: I don't know, but okay.
HER: And we'll have magic stuff.
ME: And shirts.
HER: Yes.
ME: But not magic shirts.
HER: No.
...
ME: So, I talked to Grandpa, and he can do magic at your party. What kind of cake do you want?
HER: You know, like a shirt, with magic stuff around it.
ME: Magic stuff?
HER: Yes, like stars.
ME: Around it? What about on it?
HER: No.
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ME: Those groovy shirts on Peg + Cat are cool. What about tie dyed shirts?
HER: Yes!
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ME: (Google Search: how to tie dye shirts with preschoolers)
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(At Hobby Lobby, after seeing the princess cake decorating kit...)
HER: I want a princess cake.
ME: A princess cake at your magic groovy shirt party?
HER: Yes.
ME: A magic groovy shirt princess?
HER: Yes.
ME: We'll put Grandma in charge of that.
...
HER: I want star balloons and princess balloons.
ME: At your magic groovy shirt princess party.
HER: Yes. And Pin the Tail on the Donkey...