Inspired by Sheldrake's study of fungi [Sheldrake, M. 2020. "Entangled Life: How Fungi Make Our Worlds, Change Our Minds, and Shape Our Futures." London: Penguin Random House] and Barad's idea of entanglement [Barad, K. 2007. "Meeting the Universe Halfway: Quantum Physics and the Entanglement of Matter and Meaning." Durham: Duke University Press], this paper explores music play with young children and artists, a practice that resists adult-centric approaches. As an embedded researcher within an early years arts organisation, I play with a diffractive methodology to read through ideas of Froebel with posthuman writings. Using slow-motion viewing of a video extract of musical play the vibrant agency of materials and sound emerges in micro-moments of playful music-making. Theorising with the mycelium produces ideas of extravagance, music and sound understood as lively intra-active and wild. It communicates through, and within, living and non-living matter. This view of music asks for artists to 'do' and say less, watch more and hold the space for the bursting forth of ripe and ready musical expressions. Through this pedagogical approach, children and adults can experience a sense of becoming with music, with the world.