A common project undertaken by the Sectoids and the Aquatoids is creating crossbreeds of their own race with humans. The few Sectoid crossbreeds had survived the First and Second Alien Wars, but were generally looked down upon and discriminated by humans. It was at the time of the founding of the Mutant Alliance faction in Mega-Primus that these poor souls found solace. Now full fledged members of human society, they had even taken part in the struggle against the alien hordes in the Third Alien War.
Hybrids look human with some Sectoid traits, like baldness, ridged heads and bulbous eyes. They are weak physically, but make up for this in the incredible psionic abilities they inherited from the Sectoids.
X-Com may hire Hybrid agents as long as they are friendly with the Mutant Alliance.