This, to be fair, is the usual explanation as to why celestial objects are spinning oddly or why their rotational axis is off to one side. Uranus, for example, has a rotational axis titled almost perpendicular to the Sun, and it’s thought that multiple impacts knocked it over.
“In all honesty, the evidence for which mechanism caused the tumbling is not that strong,” lead author Dr Wes Fraser, a research fellow at QUB, told IFLScience. Saying that, “collisions happen, and can happen frequently.”
“Just look at our asteroid belt for example; collisions happen there all the time. It is for this reason alone that I prefer the collisions idea over the others.”
He suggests that the original ejection of 'Oumuamua took place during the reorganization of the host system, when the planets “are in the last dregs of their growth phases, when lots of debris is left over.”
“The other methods are all viable, however unlikely, and we will never know which is the true one, because ‘Oumuamua is gone baby gone.”
Another idea, proposed in a recent arXiv pre-print, suggests that its origins was even more drama-filled than a collision or two. There’s a chance that it’s the remnant of a planet that got far too close to its host star, which triggered its fragmentation.
This paper suggests that this is a better explanation for its elongated shape than a collision between two asteroids, but this is fairly speculative at this time.
Whatever the cause, based on the rate of its spin, it’ll persist in its tumbling for at least 1 billion years until internal strain cancels out its rotational energy. Keep on truckin’, you cosmic cigar!