A secret, that is, except from the person who left it on your doorstep and the sender. How much did they know? Curious, you look over the cardboard box for clues as to their identity, but find none. What does catch your eye is that there are no markings on the box apart from your mailing address: no postage indicators, no mailing labels, not even your name. Only the address. It is possible this item wasn't even meant for you; it could be something indended for the previous occupant of your apartment, or it's even possible that the address was written wrong and it was supposed to go somewhere else entirely.
Staring at the box, you do come to one conclusion. It is likely that the person who delivered the box is not the one who addressed it, since if the person who addressed it intended to drop it off, there would have been no reason to write the address at all. Therefore, the sender and the deliverer were probably two different people. But how do you find out who they are? Maybe they have answers as to what this device is, and perhaps you can find out if you were its intended recipient. If you are not, then maybe you can figure out a way to keep it without anyone knowing it is actually in your possession.
Again, you turn the box over and over, looking for any sort of mark. You examine the device as well, but still find nothing. You do a few internet searches, but end up with responses regarding photo-manipulation software, not anything like what you have found. The scent has gone cold, you think to yourself grumpily, and get up to throw away the box.
That's when you stop and look back at the device with a crazy idea. Scent, that was the answer. Even if you could dust the box for fingerprints or something, you would still be no closer to finding the sender. However, what if you could track the scent? You even had the perfect tool to enable you to do it. Despite your misgivings, you return with the cardboard box to sit in front of the computer. Scrolling down through the menus, you find what you are looking for: "dog."
However, you do pause before actually activating anything. If you change yourself into a dog and wander around on your own, won't you just get sent to the pound? Not to mention, how would you open and close doors? Maybe you should just change your nose, although it would look a bit strange for a human to be sniffing the ground, not to mention you are not sure how to hide having a dog's nose on your face. Maybe a cat would be better? They are more dextrous, and no one would mess with a stray cat. Then again, if you are changing yourself entirely, maybe you should have a better idea of how the machine works. Nevertheless, wasting time familiarizing yourself with the device could result in you losing the scent entirely. What would the best option be?