Intruder (French: L'Intruse)[1] is a one-act play by Belgian playwright Maurice Maeterlinck, which appeared first in publication in 1890.

The clock strikes midnight, the baby commences screaming, and the Sister of Mercy appears, announcing the death of the mother.

[8] Later, Maeterlinck would explain the dominance of this element (which was recurring in his other plays) so that it was almost treated as a character in the narrative: "This Unknown takes on, most frequently, the form of Death.

For example, he invested special valence in buildings to dramatize patterns of behavior, such as the house representing a form of introversion in which libido (psychic energy) flows inward.

[11] Maeterlinck, however, employed this technique in several of his plays to enhance the atmosphere of the supernatural, horror, fear, gloom, and awe.