The Reapers are a race of aliens in the PC game X-COM: UFO Defense.  They are bipedal, brown-furred and much larger than the soldiers you command.

They have no long distance attacks and are not armed; however, they move quickly and can cause very serious damage if directly next to one of your units. They are vulnerable to incendiary ammunition. Their size (2x2 grid squares) makes it impossible for them to walk through single-square entrances, and therfore cannot attack through these entrances. Reapers are always found with Floaters, and appear on Terror missions, base attacks and with larger UFOs.