The black ox has trod upon (one's) foot proverb old-fashioned
"Black ox" implies Satan.
Used in a situation in which one experiences problems or misfortune
He was in a traffic accident a week after being fired from his job. I think the black ox has trod upon his foot.
I think that the black ox has trod upon my foot recently. Yesterday, while I was doing my online test, the power went off.
This idiom is often used to express that you should accept an unpleasant situation or event because you cannot change it.
Once something has been done, you can do nothing but face the consequences.