Consider the following sentence from 『黒流』:
At first, the second 「を」 particle might suggest that two or three of the horses, likely because they have been startled, might have caused the sleeping ones (the other horses?) to jump up. This, however, is not what is happening. Our first indication is that the verb 「飛び上がる」 is an intransitive verb. This is not what is happening, however. Instead, imagine that a verb such as 「やめて」 has been elided after the particle; the meaning would then become, “Two or three of the horses, apparently because they were startled, stop sleeping [they wake up] and leap up.”
As we discussed in class, this is odd because horses almost always sleep standing, and this verb suggests they leap from a non-standing position to a standing position, though the native speakers I asked all agreed this would likely not mean “reared up on their hind legs.” Perhaps our author was as unfamiliar with horse sleeping habits as I am.
More important is this use of 「を」, more about which I will write soon.