Maverick

Maverick (Irregular in Japan) is the name gived to Reploids that goes berserk, violent, and insane, normally due to being infected by the Sigma Virus or other type of virus. Originaly called Irregulars in the Japanese versions, they were the only enemies that would be in the levels. Mega Man X4 brought the most attention to the exisistance of non-infected Reploids when the Repliforce are branded Mavericks in their attempts to gain independence from humanity.

In Mega Man X8, it's revealed by Illumina that the Reploids can became Maverick at will, without the need of being forced by viruses or other means.