When urologists in Qatar threaded a camera into the bladder of a 13-year-old boy with months of bloody urine, they saw something that looked alive. A long, worm-like structure sat in the bladder, surrounded by debris. In the fluid-filled bladder, it even appeared to move.
The team's first thought was a parasitic infection. The real answer came only under a microscope: the "worm" was a blood clot about 10 centimeters long, roughly 4 inches.
