The XCOM Project faces a great many challenges in its fight to reclaim the Earth this November, and much of that challenge will be learning about and besting the entrenched troops of ADVENT. These troops include the evolved Sectoid soldier and cunning Viper unit.
While the Sectoid was featured heavily in XCOM: Enemy Unknown and XCOM: Enemy Within, this aggressive alien has received a sizeable upgrade in XCOM 2, all thanks to human DNA. That's right, this new Sectoid gets its imposing height and elongated bipedal features from a healthy dose of human genes. The Viper, on the other hand, couldn't be less human. Its wriggling serpent frame allows it to coil around, and crush, unsuspecting XCOM soldiers, while its deadly tongue is able to grasp and pull others towards it. As if all of that wasn't scary enough, it also carries a gun!
Check out full character profiles for each unit over on IGN.