At least, it didn't do anything other than look awesome and stylish.
BUT WAIT!
I have just now realized what we're up against! Someone stole your amulet, which is pretty much like a necklace, right? And they stole my hat, which is much like a crown insofar as they are both head ornaments.
If this thief can also steal a bracelet, a ring, and some earrings, then they will become the Pretty Pretty Princess and we will all lose!
This, combined with the hippos and their marbles on Day 1, confirms the nefarious plan, and Isaac has given us a big hint in his Night titles. Clearly, our enemy is vying for the Throne of Games, and all of us are in Trouble.