By the Great Horned Spoon!

[Douglas G. Wilson]

A Scottish 'historical' reference (I'm not convinced of its authenticity)
involving a McDougal-Duncan feud and the use of a "great horn spoon":

http://www.combs-families.org/combs/assoc/duncan2.htm

An example from Kipling ("The Rhyme Of The Three Captains", 1890):

<<The skipper peered beneath his palm and swore by the Great Horn Spoon: --
"'Fore Gad, the Chaplain of the Fleet would bless my picaroon!">>

-- Doug Wilson