The Skitterling family is a group of creatures in the Pikmin series, of which three species have been cataloged so far. Most of the Skitterling family resemble leaves, and are motionless until a Captain or a group of Pikmin comes by.
"Skitterling" is a portmanteau of "skitter," meaning to run or scurry, and "ling," a suffix meaning that something is concerned with the root of the word it is found in.
The Skitter Leaf is a harmless enemy introduced in Pikmin 2. They resemble a regular, healthy leaf. Skitter Leaves are fairly uncommon enemies, but in places where they can be found, there are often multiple.
If you approach a Skitter Leaf, they'll try to scurry away as they have no means of defense or offense. They can often be more trouble than they're worth, since they are only worth one poko and seed.
Desiccated Skitter Leaf
Desiccated Skitter Leaves, introduced in Pikmin 3, are the more hostile members of the Skitterling family. They actually have a means of killing Pikmin by grabbing them and eating them swiftly.
They resemble withered and dead leaves rather than the healthy ones Skitter Leaves imitate. The edges of the leaves are serrated and sharp, unlike its green relative. They are found in the Twilight River, so they blend in easily with the ground.
Pond Skater (while not directly proven to be a Skitterling, but is an evolutionary ancestor of Skitter Leaf) is a airborne species equipped with wings capable of flight; when not in the air, it typically found skating on bodies of water. According to Olimar's research conducted while he visiting PNF-404 with Louie to pay back the debt for Hocotate Freight, some Pond Skaters adapted to life on the dry land, losing their ability skate on water. Over time, the Pond Skaters wings became useless for flying, but they began to mimic leaves of their environment. This evolution would eventually lead to the Skitter Leaf, which shares no residual traits of its relative the Pond Skater.