The headless cattle were a species of genetically-engineered livestock produced by Montana-based rancher Wayne Butterfield with the objective to provide an alternative to regular meat that was ethically fine to eat.
Using screened genetic stock as the starting point, each headless calf was grown in an artificial womb. They were engineered to have no higher cognitive functions, and a vestigial brain only big enough so that each specimen could perform autonomic biological functions. To help regulate bodily functions, each calf was implanted a small computer chip. These chips were connected to the ranch's Wi-Fi to help keep track of the herd. The chips' connectivity resulted in an unintentional side-effect; which caused the herd to develop a combined psychic field, developing higher brain functions as a hive mind, feeling everything as one.
This mutation caused one bull of each litter to act out at random. Unable to find a reason for this oddity, Butterfield contacted Arno Stark of the Maria Stark Foundation for help. Arno analyzed the cattle and developed a calming gas with the intention to solve the issue. However, he created the gas so it wouldn't affect creatures with higher brain functions, having overlooked the herd's mutation into a hive mind. At night, the herd went rogue and stormed out of their cowshed. The stampede reached the ranch's dining room, where Butterfield and his employees were eating meat. The bulls slaughtered them in revenge. Arno managed to survive, using his ability to control his body to meditate and blend in with the animals. After escaping from the carnage, Arno called Baintronics to clean up the chaos. He also stopped them from killing the livestock, and opted to leave them alone.