Magratheans are the inhabitants of the legendary planet, Magrathea. Because their planet-building operation was so successful, they reduced the rest of the galaxy to abject poverty.

A Magrathean called Slartibartfast, as seen in the 1981 TV series.

Since no planet was rich enough to buy a planet from them, all Magratheans decided to sleep through the recession until the galactic economy returned to a level which could require and pay for their services. The only Magrathean to appear in the story is Slartibartfast.