Kids love magnets, as they provide endless amusement using one of the fundamental forces of the universe. Mega Blox debuted Magnetix, a toy consisting of various plastic building pieces with magnets inside them that could be assembled into innumerable combinations, in 2004. Unfortunately, the small, powerful magnets that made Magnetix stick together could also be easily dislodged from the plastic and swallowed by toddlers, causing serious health problems as the magnets attracted to each other inside the human body. In 2005, 22-month-old Kenny Sweet died from swallowing Magnetix, and over 30 more kids were injured before the toy was recalled in 2006.
Photo via CPSC.gov