Thin Man

Thin Men are humanoid aliens that fought against Xcom during the first invasion, they're designed to look like humans to blend in and infiltrate, being that they appear as a sort of disguised form. They have a few visual differences between humans and have the ability to spit poison. They wear a suit and sunglasses, the latter to disguise their less then human eyes. They are said to be modified versions of Vipers, which makes sense due to their more reptilian features. They wield Light Plasma Rifles, which despite the size and weight of, they wield in similar fashion to a pistol.