Prom! Beetlejuice theme?

Prom is coming up and it's my boyfriends senior year so we're going. I let him choose what we were going to wear because well it's his prom. We were trying to think if themes and he came up with beetlejuice. Like when beetlejuice and the girl Lydia get married and she's in the red dress. And well I dint where to find a dress! Basically what I want it a bug red poof prom dress. But I can't fund one anywhere! So if u know where I can find one in stores Orr online, let me know please! Thanks! (: