The T-Virus is like any other virus. It is a protein crystal with an RNA core. As the crystal makes contact with a cell's membrane, it destroys it and inserts its RNA into the cell. The cell absorbs the viral genome into its own DNA, which takes over the cell's functions. The cell begins to produce offspring of the original virus. The new viruses are then released from the host cell and infect the neighboring cells, which starts the process all over again.