Kings of Leon Drummer -- Gassy During Root Canal

5/4/2011 10:00 AM PDT BY TMZ STAFF
The man behind the gas mask is Kings of Leon's drummer Nathan Followill -- who just Tweeted a photo of himself moments before undergoing one of the most hated surgeries of all ... a root canal.

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Suuuuuuuuuuuuuuuuuuuuuuuuuuuucks.