Hmm. Yes, I do remember you speaking about your failure to dispose of the jumpsuits following the Gozer incident. [Crosses his arms.] This would align with the idea that ghosts can leave ectoplasmic "fingerprints" of PK energy, in a manner of speaking.

...Though, as this was only an "impression" of Gozer and not a complete manifestation, it would also follow that his personality or mannerisms would change drastically given enough time isolated from his native dimension.