 Among their targeted worlds is the Earth, setting up TCRI and World Wide Genome Project as fronts to collect the DNA of every animal and plant species on Earth.The Kraangs' history became intertwined with the Turtles when a small group of them caught the then-human Hamato Yoshi spying on them as they were doing business in an alleyway, and attacked him while he was holding the not-yet-mutated Turtles, then his recently-bought pets.Fighting the group to get away, he and the turtles were all mutated by exposure to the mutagen when one of the Kraang upon defeat dropped a mutagen canister, breaking it and spilling the mutagen on them.