When your highly hated ex-wife announces that she’s engaged to a highly hated singer of a highly hated band, what else are you supposed to do but dress up as them for halloween? That’s exactly what Canadian rocker Deryck Whibley did this weekend when he and a friend dressed up as ex-wife Avril Lavigne and her new fiance Chad Kroger.

But he’s not the only one who had pretty great costumes this year. Jessica Alba and her family dawned the famous red and black colors of The Incredibles, Kim Kardashian busted out a $2000 wig for her mermaid costume, and Fergie joined Ryan Seacrest at a party to wear… something. We’re not sure what they were, but we have the pictures below!

Check out who did it best and let us know what your favorite celebrity costume was this year!