If there would be something like flying dish amongst the yachts, then the Adastra Superyacht would certainly be the candidate for that kind of name. If you would encounter this yacht on sea your would probably be totally scared because it really has a frightening alien-spaceship-like exterior.
It was designed by John Shuttleworth Yacht Designs company and the building of the ship was followed by numerous controversies. It was made for nine passengers and six crew members. I reaches the length o 140 feet and is capable to develop the speed of 22 knots. If we say that the exterior is totally alien-like then we cannot say the same for the interior. The inside of the boat is really luxury, indeed, however, it rather reminds on an expensive luxury home than on the interior of some futuristic yacht.