(PerezHilton.com)
Over the weekend Deryck Whibley appeared to give Chavril an engagement present for Halloween -- although it seemed more like trick than a treat.
The Canadian Sum 41 frontman, who was married to Avril Lavigne for three years until 2009, dressed up as his ex-wife, while Whibley's girlfriend, Ari Cooper, went as Lavigne's new fiancé Chad Kroeger. Perez Hilton got his hands on a photo of the duo, who appeared to be attending a party at the time, and posted it on Sunday.
See also: Chad Kroeger and Nickelback fans sing 'Happy Birthday' to Avril Lavigne
Unsurprisingly, Kroeger was none too happy about the costumes, and the Nickelback frontman responded with a snarky tweet on Sunday.
"Hey Deryck loved the costumes! we were going to dress up as you guys this year but all the parties had celebrity themes haha! —CK," he wrote.
While Lavigne has not responded to the dig, Whibley's move comes as a surprise, considering the exes seemed to be friends up until now. The duo had a dinner date last December and Lavigne even congratulated Sum 41 on their Grammy nomination.
See also: What you may not know about Avril Lavigne's and Chad Kroeger's romantic pasts
In March 2011, the 28-year-old "I'm With You" singer admitted on "Chelsea Lately" that she was still "friends" with her former husband.
"I call him all the time, like, 'Yo, I've got a music question. Help me,'" she told Chelsea Handler. "He has such a kind heart and he's so smart. We're there for each other."
Though Whibley didn't respond to Chavril's surprise engagement, which they announced this past August, it's starting to look like he doesn't entirely approve.