Zapo has a human-like form with a square-shaped head, arms, and stubby legs. Zapo's arms are yellow with three fingers, two placed that front of his hand and one towards his body where the thumb would be, that are circular and white. Zapo's body is merged with its legs with its upper body being purple with a yellow stripe in the middle and protruding forward into a pointed slope at the front and its legs being a slightly darker shade of yellow, curved at the top, with a flat bottom.
Zapo's head is purple with a yellow stripe in the middle that stops right above a raised ridge resembling a visor, its slightly circular white eyes placed underneath the ridge and far apart, and slightly below, between the gap in Zapo's eyes, is placed Zapo's mouth that is yellow with a jagged top.
It was revealed at the end of Fault Line that the Zapo is a test robot placed in an area with white nodes.
Zapo has the power to separate its hands from its body and use them to connect White Nodes to morph the level it is on. Zapo is relatively weak, taking only one hit to be destroyed. On the other hand, it can be considered powerful by being able to re-construct itself at the last check-point it touched. This is very similar to how Blue acts during the Test Subject series, a similar series of games to Fault Line.