Mutons are another type of alien the XCOM units will face in the upcoming "XCOM: Enemy Unknown". They are rumoured to have a special ability known as "Blood Call" and to possess group combat bonuses.
Taken from the original game
This humanoid creature is physically powerful and intelligent. They have a particular appetite for consuming raw flesh of any kind, which they need for sustenance like earth based carnivores. They appear to rely on telepathic commands from a race know as 'Ethereals'. Once separated from this telepathic link their mental system appears to break down and they die. The cybernetic implants are used to enhance their combat performance. They are clearly the foot soldiers for a higher intelligence.