Great-grandfather Angus

Great-grandfather Angus was a relative of Abigail Sleuth.

Physical appearance
He looked like Shaggy Rogers with black hear.

Scooby-Doo! (DC Comics)
According to Abigail Sleuth he helped Sherlock Holmes find his violin. ("Ah...Rival")

Appearances

 * Scooby-Doo! (DC Comics)
 * #142(a). "Ah...Rival" (picture)