In the Rikti War Zone, they are Level 35 (the lowest level allowed in to the zone) and are designated "PracticeBot" from the faction "Practice Robots". They are immobile and have no attacks. They also resist 100% of all damage, and therefore cannot be used to obtain inflict damage badges.
A training dummy. It allows trainees and pros alike to get used to hand to hand combat against the Rikti foes.