  1I/`Oumuamua is the first known interstellar small body, probably being only
about 100~m in size. Against expectations based on comets, `Oumuamua does not
show any activity and has a very elongated figure, and also exhibits undamped
rotational tumbling. In contrast, `Oumuamua's trajectory indicates that it was
moving with the local stars, as expected from a low-velocity ejection from a
relatively nearby system. Here I assume that `Oumuamua is typical of 100-m
interstellar objects, and speculate on its origins. I find that giant planets
are relatively inefficient at ejecting small bodies from inner solar systems of
main-sequence stars, and that binary systems offer a much better opportunity
for ejections of non-volatile bodies. I also conclude that `Oumuamua is not a
member of a collisional population, which could explain its dramatic difference
from small asteroids. I observe that 100-m small bodies are expected to carry
little mass in realistic collisional populations, and that occasional events
when whole planets are disrupted in catastrophic encounters may dominate
interstellar population of 100-m fragments. Unlike the Sun or Jupiter, red
dwarf stars are very dense and are capable of thoroughly tidally disrupting
terrestrial planets. I conclude that the origin of `Oumuamua as a fragment from
a planet that was tidally disrupted and then ejected by a dense member of a
binary system could explain its peculiarities.
