(Capcom's primary storyline)
An "irregular mutant" is a creature birthed from a secondary viral infection, particularly from the t-Virus, but was not intentionally created, or a deviation in intended genetics from a standard B.O.W. plan. An example for the former is Zombie Elephant, an infected elephant; it was not infected as an experimental B.O.W., but instead inadvertently as a consequence of the biohazard. An example of the latter is the Glimmers, who were inadvertently created through an unintended mutation within Umbrella's Hunter B.O.W. line.