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Since I was the one that smelt it, I would forever be... he who dealt it!
— The Spleen • Mystery Men

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
This is a groan-worthy rhyme built on the old playground saying 'he who smelt it dealt it'. The speaker realises that because they noticed the smell, they'll forever be blamed for it. The joke is the tiny embarrassment turned into a permanent, sing-song reputation.
Context reviewed