Could be a black cat crossed the plant's path, the rotation of the moon shifted, or someone told it something bad. We can speculate but until you give us details beyond photographs, we can't do much more than that. We need specs to help you.
What are you growing in? If soil, did you buy it bagged or mixed it yourself? If mixed, how did you do that? If using nutrients, what line and how much of each? pH of feeding solution? EC? What about temperature? Humidity? Looks like your outdoor, so has this plant been outside all its life or moved from inside to out? Details are vital, no matter how minuscule they may seem.
Not trying to be a dick, but without details we can't help you much.
One Love,
tobh