Casspring are dark green bug Pokemon, with two long antennae and large legs ending in coil shapes. It has a pair of miniscule wings, and bright yellow eyes. Its black forearms are rather small, and it has a small, stubby tail. Its head has a large, black covering, and the rest of its body alternates between black and green stripes.
By coiling up its legs, Casspring can jump up to fifty feet in the air. Once in the air, it can flap its wings one hundred times per second to stay airborne. If it jumps high enough, it can kick opponents powerfully. Casspring can also focus on distance rather than height, and can jump away from predators quickly. Casspring are rarely seen on the ground, but can be spotted easily when flying.
Casspring is very timid, preferring flight over fight(literally). However, it can be swayed if tempted by its favourite food, lettuce. In the wild, Casspring are omnivores, usually eating plants and leaves but also grabbing small insects mid-flight. They also seem to have an aversion to large flashes of light, making it hard to take a photo of them and causing them to hide when thunder is heard.
Casspring will live anywhere that there is food and water. However, they seem to have an affinity to places with lots of tall rocks, slopes, and crags, such as Victory Road.
Casspring's legs act like springs, rendering them capable of jumping very high. It is often for people to be startled when they land from the sky out of nowhere.