Enlarge (credit: Don Henderson via Getty Images) Think of the worst invasive species you know. Kudzu: smothering trees and houses, growing a foot a day. Burmese pythons: stripping the Everglades of small animals. Asian carp: hoovering streams clean of plankton and swimming toward the Great Lakes. They all came from somewhere else, arrived with no natural predators, outcompeted local flora and fauna, and took over whole ecosystems.