Tracked Robots are a type of robot which use treads or caterpillar tracks instead of wheels. Mortis was the first of its kind to appear in Robot Wars, debuting in Series 1 and winning the Series 4 War of Independence in its final appearance. Other successful tracked robots include Series 2 Semi-Finalist Plunderbird 2, Series 3 Semi-Finalist 101 and Dutch Series 1 champion Slicer. The House Robots Sir Killalot and Mr. Psycho also used tracks as their means of locomotion.