This article studies the function of the iconic sign and the operation of diagram-icons in Lars von Trier’s The House That Jack Built (2018), a film about a serial killer Jack (Matt Dillon) who builds a house of corpses before being escorted to hell. What is remarkable in this film is von Trier’s specific use of filmic iconicity in probing the value of Western icons in art and architecture. In voiceover digressions from the narrative action following Jack’s serial killing, a comparison is made between the iconic power of murder on a grand scale (specified as genocides throughout history) and culturally valuated icons of art and architecture. The article focuses on the audiovisual icons in the film that invites the audience to diagrammatic readings and fabulation throughout and beyond the film’s narrative content. After a short introduction to the iconic sign and the diagram-icon respectively, the exploration of the film takes its starting point in how Jean-Luc Godard used the iconic force of the color red in Pierrot le Fou (1965). Even though the significant use of red throughout The House That Jack Built is justified within the context of serial killing, its many reiterations also qualifies ‘red’ as a diagrammatic feature combining iconic elements transversally. This diagrammatic feature foregrounds the film’s fabulatory and haptic levels beyond its strictly narrative content, making way for the wider philosophical comments expounded ‘in the film’ by the figure of Verge (Bruno Ganz). His extradiegetic voice becomes intradiegetic in the last part of the film as his body appears, acting as a guide for Jack into a version of Dante’s hell.