Annihilation is Alex Garland’s 2018 science-fiction film, and its score is by Ben Salisbury and Geoff Barrow of Portishead, who had already worked with Garland on Ex Machina. Most of the film is carried by finger-picked steel-string guitar and the waterphone, an instrument that cannot be tuned and whose wavering metallic tones suited the Shimmer, the mutating zone at the heart of the story.
Synthesisers are held back until the lighthouse sequence, where the cue known as The Alien unfolds over twelve to fifteen minutes in four sections, combining orchestra, electronics and voices around a four-note motif whose harmonic seeds are planted in the earlier guitar and waterphone cues. Garland, the film’s editor and its music editor assembled the final version from the composers’ material. The result turns the film’s quiet unease into a slow, engulfing climax of sustained sound, which the composers framed as a balance between beauty and fear.