Researchers from Princeton University and the University of Basel found that a mechanism used by many disease-causing bacteria that was once thought to be a microbial superweapon can be thwarted if the cells being attacked are numerous enough. The weapon, known as the type VI secretion (T6S) system, injects target cells with toxic proteins. The fluorescent-micrograph film above shows the bacteria Vibrio cholerae (green), which have T6S, attacking the bacteria Escherichia coli (black), which are vulnerable to the secretion. The first five seconds of the film show V. cholerae taking over the small, scattered groups of E. coli. The latter half of the film shows that the larger, more unified E. coli colony is able to expand because the attack is concentrated on the group's outer border.