The fattest hog in Epicurus' sty.
Source, in full
Heroic Epistle, reported in Bartlett's Familiar Quotations, 10th ed. (1919). Compare: "Me pinguem et nitidum bene curata cute vises, ...Epicuri de grege porcum" (translated: "You may see me, fat and shining, with well-cared for hide,—…a hog from Epicurus' herd"), Horace, Epistolæ, lib. i. iv. 15, 16.