Haggis is a savoury pudding containing sheep's pluck (heart, liver, and lungs); minced with onion, oatmeal, suet, spices, and salt, mixed with stock, traditionally encased in the animal's stomach though now often in an artificial casing instead. According to the 2001 English edition of the Larousse Gastronomique: "Although its description is not immediately appealing, haggis has an excellent nutty texture and delicious savoury flavour"
Yeah, I'll agree that it's description is not immediately appealing. A vast understatement.