OPI Black Tie Optional, a deep purple beetle multichrome from the 2001 World Collection, is one of the classic hard-to-find polishes.
I lemminged this one forever until I finally decided to just splurge and get one on ebay. I’ve noticed that some bottles of OPI Black Tie Optional have more of the multichrome beetle effect than others. Mine is a dud *sigh*. The beetle effect is there but it’s very subtle so I couldn’t get a very good picture of it. The non-dud bottles flash gorgeous amber, green, and red.