Stubby Boardman

Stubby Boardman was the lead singer of a musical group called the Hob Goblins, who retired in 1980 after having a turnip thrown at him during a concert in Little Norton Church Hall.

Mistaken Impressions
He is mistakenly thought by some (such as Luna Lovegood) to be Sirius Black, due to having a similar appearence to him. There is an article in the magazine The Quibbler, edited by Xenophilius Lovegood, that elaborates on this theory.