History
Adam Cross, along with several other first responders, aided in the recovery after the Chitaruri invaded New York where they kept a souvenir alien helmet. Months after, Adam, Frank Whalen and Tony Diaz decided to polish the helmet. The helmet carried an alien virus, which Adam contracted.
While out as a scout leader, Adam began to feel the effects of the virus, and was eventually killed by it. The virus caused the body of the victim to float in mid air after death, While Jemma Simmons was investigating the body of Cross, a spark jumped from Adam's dead body to Jemma, transmitting the virus to her. [1]