The Arcateenian hearse was a spaceship used by the Arcateenians to ferry the dead.
After their liberation and subsequent enslavement of Tivoli in the late 20th century, the Arcateenians provided a hearse to transport the body of the Fisher King. It was piloted by the Tivolian undertaker Albar Prentis, who was charged with burying him on "a barren, savage outpost" in accordance with Arcateenian custom. However, the Fisher King was not really dead, and burned markings into the wall. (TV: Before the Flood)
In 2119, the spaceship was in the Drum, an underwater mining base, where all the crewmembers saw the markings. This made them targets for the ghost transmitters created by the Fisher King. (TV: Under the Lake)