أَوْ كَصَيِّبٍ مِنَ السَّمَاءِ
Or like a heavy rainstorm descending from the sky.
In Qurʾān 2:19, the comparison marker «كَـ» precedes the word for a downpour. The fuller passage also describes darkness, thunder, lightning and the reactions of those caught in the scene. The rhetorical object is therefore not exhausted by naming rainfall.
This is an example of a short comparative expression introducing a broader developing image. Identifying the formal marker is only the beginning; the interpreter must also reconstruct the relevant scene rather than treating the isolated image word as a complete statement of the point of resemblance.