You remove the tissue paper and find what appears to be the uniform of a police officer. Blue shirt, white undershirt, navy blue pants, black shoes, and the hat. Under the clothes is another, smaller box. Opening that you find what appears to be a donut and another note. You look at the note, hoping it explains the strange gift.
"Be sure to put on the entire uniform before eating the bearclaw. I look forward to being 'arrested' tonight. Will you be a good cop or a bad cop?"
After reading that, you're not sure if you want to meet your admirer, its sounds like whoever sent the box has some weird fetishes. Deciding not to worry about your date for now, you pick up the uniform. Maybe you'll try it on just for fun, see how you look in it.
The box didn't come with any underwear, for which you are grateful, that would have been just a little too creepy if the package contained that. Keeping yours on, you strip off everything else and put on the costume. You realize that if you do go out, you should cover this thing, no use getting arrested for impersonating a real officer. You finish buttoning up the shirt and place the cap on your head, fully dressed in the uniform. You look in the nearest mirror and see... well, you in a slightly loose police officer costume. "Guess she overestimated my size," you think, at least you hope it's a she.
Walking back to the package, you remember the second note and the donut, a bearclaw as you recall. "What the heck?" you think as you pick up the pastry, downing it in a few bites. An acute sensation of nausea washes over you, causing you to drop to one knee until it passes. Did the donut go bad? Could it have caused such a bad reaction?
Once the room stops spinning, you stand back up. It's odd, you feel perfectly fine after the feeling of sickness ended. You pass by the mirror again. But it's not your original image reflected in the glass.