[Suicide Junkie]

Hey, for a ghost ship, you should have it use only the most basic tech: DUCs, shield 1s, ion engines, armor 1, etc.
But, give it a "ghost hull" shipsize, that gets an inherent 1000% defence bonus, so everybody has a real tough time hitting it.
For missiles, put a PDC on it with zero reload and 1 range, called ghostly aura. Any missile or fighter will be killed instantly as soon as they approach.

The only way to kill this ship would be with a talisman, or to ram it and suffer damage.