Some people, it would seem, are seriously looking at the possibility the Oumuamua asteroid may be an alien spacecraft. It has exhibited some peculiar features – not least its pencil slim shape and its high speed. See www.scientificamerican.com/article/alien-probe-or-galactic-driftwood-set… … is it a piece of galactic driftwood passing through our solar system or could it be an alien space ship.
At www.scientificamerican.com/article/oddball-object-tumbling-among-the-sta… … we are told oumuamua is more likely to be a defunct comet rather than an asteroid. Its spinning motion suggests it may have been experienced outgassing activity. Interpretation is a matter of guesswork as it seemed to show no increased activity when it came closest to the Sun on its journey through the solar system. See also www.space.com/39100-interstellar-object-oumuamua-alien-life-search.html