Katie Laushman remembers her first encounter with Amynthas agrestis. It was 2014, and the UW-Madison graduate student was working on an oak savanna habitat restoration in the UW Arboretum when a work crew member asked if she’d heard about the gardens’ newest inhabitant. He took Laushman over to a mulch pile and brushed away the top layer to reveal a bunch of writhing, wriggling earthworms.