Castalius rasimon, commonly known as the Common Pierrot, is a small butterfly belonging to the Lycaenidae family. It is predominantly found in the tropical and subtropical regions of Asia, including India, Sri Lanka, and Southeast Asia.

The Common Pierrot exhibits a striking appearance, characterized by its white wings adorned with bold black spots and bands. The upper side of the wings is primarily white, while the underside is light gray with subtle patterns that aid in camouflage. Males are often more vibrantly colored than females, making them easier to identify during flight.

Known for its agile flight, Castalius rasimon is a frequent visitor to nectar-rich flowers. While it is generally considered a common species, habitat destruction and changes in land use may impact its populations. Overall, the Common Pierrot adds to the rich biodiversity of its environment and serves as an important pollinator in its ecosystem.