Prudic watched the same video as her colleague but came away with a different opinion. "We all think that Obama is a ninja," she wrote in an email. "But watching the video, those seemed like larger, slower flies." Since the 44th president was able to knife-hand strike the pests, she thinks that they might be cluster flies, Pollenia rudis. This species is bigger than the housefly and easier to kill by hand. It also has a completely different reproductive strategy. Cluster flies lay their eggs in soil; when the larva emerges, it begins to seek out earthworms. Once the young pest finds a worm, it begins to eat it alive until the larva is ready to pupate into an adult cluster fly. They usually only come indoors for the colder months and "cluster" around the windows of a warm building—hence the name. "My guess is that they're waking up from hibernation and they're in the White House," says Prudic. "And it's like this giant maze."