Send them back.
3 seconds sound clip from the Dune (1984) movie soundboard.
You can hear this line at 02:48:23 in the Blu-ray version of the movie.
Quote context
[...]
- How dare you speak to me in...
- You have some idea of what I could do.
- Don't try your powers on me.
- Try looking into that place where you dare not look. You'll find me there staring back at you.
[...]