VIDEO: Godsmack frontman, a Patriots fan, sings 'Seahawks Sucks' ... in Seattle

Sully Erna supports the New England Patriots, no matter what.

Just ask the Seattle crowd that foolishly started a "Seattle Seahawks" chant and heckled the Godsmack frontman about his beloved team during a concert last week.

Sully wasn't going to take that lying down. With guitar in hand, the Massachusetts native sang a sweet song called "Seahawks Sucks," rife with more expletives than a typical football locker room.

Warning: Very NSFW language

Never mess with a man and his football team.