An ethereal dreadnought pursues a traveler across dimensions. (Jeff Easley from the AD&D Manual of the Planes by Jeff Grubb, TSR, 1987.) In later editions this creature was known as an astral dreadnought.
Astral Claws Venerable Dreadnought - The Astral Claws were a Space Marine Chapter who turned Renegade in M41. Their survivors exist as the Red Corsairs, and their Chapter Master, Lufgt Huron, is now the infamous pirate lord Huron Blackheart.