Green’s Dictionary of Slang

the extreme example, the most outstanding (of a kind).

1907		S.E. White Arizona Nights 193: Speakin’ of snakes [...] I mind when they catched the great-grandaddy of all the bullsnakes up at Lead in the Black Hills.
1946		Mezzrow & Wolfe Really the Blues 22: The Roamer Inn was like a model of all the canhouses I ever saw [...] the granddaddy of them all.
1956		R.C. Simonini ‘Lapses in Radio ... Speech’ AS XXXI 255: This is known as the ‘grandaddy’ of all bloopers.
1962		P. Crump Burn, Killer, Burn! 333: Death, the grand-daddy of all pains.
1977		J. Sayles Union Dues (1978) 89: What should I find but the grandaddy of all turds a settin there before me.
1987		‘Joe Bob Briggs’ Joe Bob Goes to the Drive-In 61: The Wild Angels (1966) Granddaddy of the biker movies.
1991		B. Hamper Rivethead (1992) 226: Driving down I-75 on my second day on the job, I had the grandpappy panic attack of them all.
2001		N. Tosches Where Dead Voices Gather (ms.) 237: It was the granddaddy of all rigged games, for Yahweh remained free.