Standing in front of a mirror, the speaker doesn't recognise what they see. The eyes and mouth in the glass feel like they belong to someone else, and the mouth opening "dumbly" looks almost like a ghost. The line "I destroy you" is startling: the speaker seems to turn on the reflection, as if wiping out the image might get rid of the stranger.
The second half grows more desperate. In the dark, the face disappears altogether, and the speaker asks where it has gone. Then comes a kind of ritual: a "pass" made before the mirror, a gesture that reads like a spell meant to "dispel reflected terror." The speaker wants another face put in place of this one, and wants the old one to "shrivel up." The poem suggests a deep unease with the self, a fear of being looked back at. The mood is eerie, tense and claustrophobic, helped by the short lines and bare, abrupt phrasing.