A person of the opposite sex used to distract you for a short period of time, not intended for the long term.
Kelly hooked up with Rob last night, but she's not interested in dating him, he's just a shiny object to her.
The distracting item, person, or activity that keeps you from doing what you should be doing.
Something unintentional or unforseen that distracts you from getting anything done or goals accomplished.
Marlene was working at peak efficiency when opening up her email became the "shiny object" to her day.
I really wanted to be productive this weekend, but my kid getting sick became my shiny object.