Autracks are mechanical enemies found on SR388 likely of Chozo origin. They only appear in Metroid II: Return of Samus. They are Chozo machines in SR388 meant to serve as guardians. Like other Chozo machines on SR388, it is unknown why they attack Samus and not nearby aggressive creatures. These enemies retract and extend very quickly, upon expanding they shoot out a single laser shot. These shots or the Autrack itself can be frozen with the Ice Beam. Autracks do not turn around, thus are easily defeated once Samus jumps over them. Also, because they cannot turn around and because they often give large energy units, Autracks are easy to take advantage of by entering and exit a room behind it, killing it over and over for energy. Before jumping over them, however, their quick shots can pose problems. There are often areas directly in front of Autracks that Samus can use to take cover in.
The Autrack's name is likely a portmanteau of the words "auto" and "track". This could reflect how it automatically retracts and extends on a set track or rail.