And whatever DNA they had in cryogenic lead containers. Or perhaps the AI machines can print DNA based on blueprints the originator species stored in the AI memory with nano scale printers. Von Neumann machines are something we may soon be capable of building. Our species may not be around on Earth by the time the first of them reach other stars, but an element of humanity will persist.
Unless someone can demonstrate a realistic theory of hyper drive, or traveling through wormholes automagically, Von Neumann type probes represent the most realistic means of interstellar exploration/colonization from an Extra-terrestrial hypothesis angle as it relates to UFOs.
The inter dimensional/demonic hypothesis requires no interstellar travel, only the ability to manipulate human perception. The problem with this theory is that decidedly non-human perception based physical effects seem to have been recorded on radar/film/alleged landing sites.
Anecdotal evidence suggests that both may be in play. I can only rely on the anecdotal evidence of my own eyes in the wake of a daylight disc sighting (guesstimate around 2000 feet in altitude) and another night time sighting of a low flying, structured disc (guesstimate traveling from below my hilltop position to around 1000 feet straight over my head) .
That being said, pretty much 99.99999% of the video you see on Youtube is either fabricated or a bird.
I pretty much only believe fellow pilots.
I guess I resemble that remark. So try this to whet your whistle. The whole interview is well worth it...and the guy is a pilot, a retired Major, USAF.
This link just drops person at the end for a punchline. (Then rewind to see the whole interview.)