Invasive Species Invasive marine species can be aggressive ecosystem engineers, dramatically altering new habitats by overgrowing preexisting species and threatening coastal ecology. Pyura praeputialis , an intertidal tunicate indigenous to the southeastern coast of Australia, invaded the coastline of Chile a few hundred years ago. The species is present, so far exclusively, along 70 kilometers of rocky coast inside the Bay of Antofagasta, where it has become ecologically dominant. Hudson et al. combined species distribution models and genomic data to understand the invasion history of this tunicate and what potential habitats might be available adjacent to its current introduced range. Although animals from a single region of eastern Australia contributed to the colonization of the Bay of Antofagasta, the population shows high genomic diversity and considerable adaptive potential. The authors identified more than 3500 kilometers of coast along the eastern Pacific at potential risk of invasion. Slight changes in currents and human-assisted contamination could help the spread of this damaging sea squirt. Proc. Natl. Acad. Sci. U.S.A. 118 , e2022169118 (2021).