People
He has turned almost alarmingly blond — he’s gone past platinum, he must be plutonium; his hair is coordinated with his teeth.
— Pauline Kael

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
A jokey description of very bright blond hair. The critic says it has gone beyond platinum, so it must be plutonium, and adds that it matches his teeth. The humour is in escalating the metals and treating hair and teeth as a coordinated set.
Context reviewed