REM behavior disorder (RBD) is a neurodegenerative brain disorder that causes abnormal sleep phenomenon in which individuals act out their dreams. Individuals RBD have been observed flailing their arms and legs as if defending themselves against imaginary enemies. In some severe cases, people with RBD have gotten out of bed, driven cars, harmed themselves, and assaulted family members. In one of the more frightening cases of RBD discussed during the lecture, a police officer awoke with his gun pointed