The caterpillar as seen in the startup for Flash Cat
The caterpillar consists of a lime green oval with three pink legs on each side in the levels. On the front of its body is its head, which consists of two levers to hold on to and two antennae. It is possible that the levers control the caterpillar.
The caterpillar's actual face is not revealed, unlike the Flash Cat, who has half of its face revealed in levels. In the startup, the whole caterpillar can be seen with a large, long lime-green body and two beady eyes with numerous pairs of legs.
The Flash Cat rides the caterpillar for the entire course of the game. The Flash Cat uses the caterpillar as a vehicle. The caterpillar has three health, like the Flash Cat, and explodes when hit three times.
Whenever a power up is picked up, when it is used, the caterpillar is commanded by the Flash Cat to be used. The Flash Cat does not use the pick up itself, the caterpillar initiates the pick up to be used, which is used on itself.
- A very long caterpillar in the startup of Flash Cat appears, with the word "NITROME" on its back. This caterpillar does not have levers attached to its head.
- The caterpillar the Flash Cat rides may be robotic, or semi robotic, as the levers seem to go into its head.