Satchī (サッチー, short for "Searchmaton" サーチマトン Sāchimaton) is a bot and antivirus software deployed by the Cyberspace Administration of Daikoku. Its task is to debug and maintain the virtual side of the city. Its secondary function is to seek out and disable illegal AR devices, software, and viruses, making it a menace to the characters of the series. Searchmaton can deploy up to four spherical drones to aid in its task. While Searchmaton can patrol the city streets freely, it is prohibited to enter private property such as houses, and other spaces such as temple grounds and schools, because they lie outside of the responsibility of Daikoku's Cyberspace Administration. The protagonists utilize this and other predictable aspects of Searchmaton's behavior to escape its grasp. Searchmaton, striking terror into the hearts of children, is ironically painted with a smiley face and punctuates its violent attacks with the cute catch phrase "I'm Satchī!" (僕サッチー boku Satchī?) which Yasako's father had a part in developing. Tamako often hijacks Searchmatons for use as her personal digital henchmen. They are later replaced by the upgraded Searchmaton 2.0 in the form of cubes which have upgraded weapons and shielding, and can combine like the Q-chan to perform wide area re-formatting. Since the 2.0s are under government jurisdiction they can enter areas inaccessible to Satchī including shrines, and also private property when authorised.
(Source: Wikipedia, the free encyclopedia)