A Tachikoma (タチコマ) is a fictional artificial intelligence, walker/roller in the Ghost in the Shell universe created by Masamune Shirow. Nine of them are assigned to Section 9's use originally. They are spider-like, multi-legged combat vehicles, equipped with artificial intelligence.
Tachikoma are controlled by individual AIs, are capable of speech and generally exhibit a childish, curious, joyful and active personality, although they are consummate professionals in the field. They normally operate as independent units and receive orders from human agents, but they can also be directly piloted from a cockpit in their abdomen.

Source: http://en.wikipedia.org/wiki/Tachikoma