Blizzard has recently added a new unit page to its site. This unit is a classic unit that all Protoss have come to love: the Observer!

Excerpt from Blizzard.com:

These small drones are employed to survey vast wasteland areas or observe and record battles for study within the protoss archives. Their complex sensor array leaves little energy for defenses, but they can detect cloaked or concealed enemies with ease. This ability makes observers invaluable auxiliary units on the battlefield.

You can read more about this unit as well as watch it in action here!