In the present chapter, we explore how emerging natureculture assemblages are materially and semantically transforming ecological life-supporting systems today. To this end, we focus on the “plastisphere”, the ecosystems that have evolved on underwater plastic waste of the Anthropocene in marine environments (e.g. relicts, ghost nets, infrastructures and polluted sites…) and that already infiltrated the global biochemical systems. This represents a forefront topic of research that interrogates natural and social scientists on the ontology, the pragmatic consequences and the semantic meaning of the heterogeneous formations derived from recombinant biological processes in the marine environment. Following Donna Haraway’s conceptualisation of the Chthlucene, we conceive the plastisphere in terms of sympoiesis between non-human and human life embedded in a liquid and turbulent world of submerged connections that forge new oceanic kinships and call for a tentacular way of thinking about our earthly relationships and responsibility. The visual documentation collected in the Mediterranean Sea during the EU “SeaPaCS. Citizen Science against Marine Pollution” project helped us visualise the plastisphere emergent ecologies.