A movie shows the rapid forward locomotive acceleration of animals with an O2-ON response. Animals were initially deprived of O2 for 5 minutes as indicated with a red bar, followed by reoxygenation as indicated by the disappearance of the red bar. Each animal is labeled with a different color. The lengths of tracks indicate extent of the worms' locomotion during the previous minute and thus reflect the speeds of the animals. This worm behavior, the O2-ON response, models key aspects of ischemia-reperfusion injury response in mammals. This video relates to a paper that appeared in the June 27, 2013, issue of Science Express, published by AAAS. The paper, by Dengke K. Ma at Howard Hughes Medical Institute in Cambridge, MA, and colleagues was titled, "Cytochrome P450 Drives a HIF-Regulated Behavioral Response to Reoxygenation by C. elegans."