Tachikoma's are small spider legged tanks equipped with advanced artificial intelligence. They normally operate as independent units and receive orders from humans, but they can also be directly piloted from a cockpit in their abdomen. (with a saddle and control arrangements similar to a motorcycle) Their design is implicitly based on that of the jumping spider. 

Though they possess individual artificial intelligence, every night they are synchronized, so they start the next day with identical consciousnesses that are each the sum of their total collective experience and development. This leads to identity confusion, since each Tachikoma has the same memories.