What should I wear to our Sadie Hawkins Dance?

I'm a Junior, and can either wear a dress (short, not floor length) or some random costume-y thing (upperclmen come up with themes to dress up as, and I'm supposed to wear something gem related, like jewel colors or sparkly things). I'm almost 5'4'', really really pale skinned, and have dark brown hair and brown eyes. My measurements are 36-24-36. Help please, what should I wear?! Thank you!