In the phase of environmental crisis, we must consider sustainable and eco-friendly options when choosing building materials. This project proposes a new material culture based on the sea and its inhabitants as an alternative to cement and concrete, using an available residual stream from the Dutch coast. The result? Seacrete. Oysters and mussels are abundant sources of lime. When Seacrete dissolves it adds value to the landscape. It gradually wears away like cliffs eroded by the wind and sea, creating a beautiful living landscape. This material culture offers an exciting new direction in eco-friendly building materials and takes a step towards creating nature-inclusive materials for the symbiocene. This project Advocates who recognize that human survival depends on coexisting with nonhuman life. By sharing materials with natural ecosystems, Seacrete enriches marine habitats as it dissolves, fostering biodiversity and circular, life-supporting cycles. Embracing erosion and sea-level rise, this project demonstrates that thriving means designing for all species, not just our own.