"The Olafs" are a group of vikings only seen in the episode Dear Vikings. It is really unknown why all their names are Olaf.
Squidward: Sure! I'll teach ya. Listen closely now. The Vikings were....
Vikings: (standing, some with weapons)
Squidward: a race of scholars and scientists who lived before even Mr. Krabs was born.
Viking: (puts ketchup on a hot dog)
Viking: (eats a hamburger)
Squidward: They are believed to have discovered ketchup....
Viking: (holding a leash)
Squidward: and enjoyed dressing up their pets as....
Brick with legs: (tied to a the leash. It barks)
Squidward: scrambled masonry on the weekends.
Vikings: (watching a movie on a projector screen. It shows two fish in a car)
Squidward: Their favorite movies are in black and white.
Guy with axe on projector screen: (appears)
Viking: Look out!!
Other Vikings and guy with axe: Sssshhhhhhhhh!
Squidward: And grown Vikings are known to collect socks which they display and trade at monthly sock trading conventions called Sock'n Garten.
Vikings: Sock'n Garten.