How could I give someone nightmares?

Is there a incantation or ritual I can do to give someone nightmares?

I know, I know, a bit ago I was against this kind of stuff, but then I though, if you can’t beat em, join em. So I figured I’d ask about something Ive been curious about for a while.

Have you tried using the search function? Because there are other threads asking this same question, like this one: