Spore-like cells were proposed to be pluripotent cells that lie dormant in animal tissue and become active under stress or injury as adult stem cells, exhibiting behavior characteristic of spores. They were proposed in 2001 by brothers Charles and Martin Vacanti and colleagues.[1][2] Further work in collaboration with Japanese researchers led to the apparent discovery of STAP cells, in which the pluripotent cells were newly created by stress or injury. This work was published in 2014, but soon found to be due to fraudulent work by Haruko Obokata.