Well, we all know that Avril Lavigne is now engaged to the lead singer of Nickelback, Chad Kroeger, but remember when she was married for a hot minute to the lead singer of Sum 41, Derek Whibley? Well, Derek took a chance to make fun of her and her new fiance by dressing up like them for Halloween! Apparently Chad Kroeger didn't see the humor because he responded on Twitter by saying, "Hey Deryck loved the costumes! We were going to dress up as you guys this year but all the parties had celebrity themes." To see them dressed up as Avril and Chad, click here!