Guardian Stalker

Guardian Scouts are the most common variation of the Guardian enemy in The Legend of Zelda: Breath of the Wild. They were originally programmed to protect Hyrule from Calamity Ganon, but were instead taken control of by the beast and used against Hyrule. These Guardians look like massive spiders infused with Sheikah technology, similar to their Sheikah Slates. They have a single eye, and are capable of firing a massive laser from this eye, capable of killing almost anything in a single hit.

Combat
Guardian Scouts usually patrol around a certain area, watching for invaders. When a Guardian spots a living creature, it will begin crawling towards it, charging it's laser, and then firing. They repeat this process until the target has been eliminated.

Certain weapons are extremely effective against Guardians, known as the "Guardian" or "Aincent" weapons. Guardian Arrows, specifically, can instantly destroy a stationary Guardian Scout missing it's legs when shot directly in the eye. Guardian Swords, Guardian Spears, and Ancient Battle Axes can cut off a stunned Guardian Scout's legs, leaving it stationary. A Guardian can be stunned by being shot in the eye with any type of arrow. A Guardian Shield can deflect a Guardian Scout's laser back at the Guardian Scout by correctly timing a parry.

Trivia

 * According to Eiji Aonuma, the main director of Breath of the Wild, the Guardian Scouts were based on the Octoroks from the original The Legend of Zelda. Since Link's sprite is roughly the same size as that of the Octoroks, Aonuma saw the Octoroks as massive compared to Link. They had originally planned to create a giant octopus enemy for Breath of the Wild, but decided that was too disgusting. They eventually settled on the Guardian Scouts, which were actually the first technology designed for the game. This drastically changed the direction of the game, giving rise to other technology, such as the Sheikah Slate and the Divine Beasts.
 * The Guardian Scout was the first enemy designed for Breath of the Wild.