Rome - (Sieg Heil!): Using Viennese dwarves who had undergone extensive plastic surgery Adolf Hitler's crack SS division came up with the brainwave caper to get inside the minds - if not bodies - of the wartime Vatican.
Recently declassified files have revealed the Nazis hatched the plot amid fears Hitler's Pope Pius XII might have gone off-message.
The highly trained altar boy corps was airdropped into St Peter's Square and immediately became a runaway hit with Curia officials.
Vatican officials 'were blind' to any possible subterfuge, mermerised by the angelic faces and fetching costumes.
Some files note the altar boys' mission backpacks also contained noxious psychotropic substances labelled 'church incense.'
"Christmas 1940 Midnight Mass at the Basilica was a right hoot!" contemporary witness diaries reveal.
"They packed the thuribles with Premium Grade Obergruppenfuherer Skunk No 1," one memoir relates, "and substituted 100-degree proof Russian Krupnik for the usual vin ordinaire altar wine."
The ensuing party in the Catacombs lasted well past New Year's Day.