The T-virus is a fictional virus from the Resident Evil video game series created by Capcom. It is known for its ability to reanimate dead tissue, leading to the creation of zombies and other mutated creatures. The virus was developed by the Umbrella Corporation as part of their bioweapons research. In the series, the T-virus spreads through bites or contact with infected blood, causing severe symptoms in humans, including loss of higher brain functions. The outbreak of the T-virus leads to catastrophic events, prompting survivors to fight against the infected and uncover the truth behind the virus's origins.