Cassandra is a character created by Newgrounds founder Tom Fulp and the main antagonist of the 1999 Flash game Pico's School, as well as a recurring rival of Pico in the Pico series. She is a rebellious and non-conforming goth girl who is secretly a Penilian, an alien lifeform from outer space. She is the leader of a gang of students who consider themselves to be outcasts named the "Goth Punks", whom she influences to help her commence a school shooting. In Pico's School, she faces off against Pico at the end of the game as the final boss, revealing her true extraterrestrial self. She is a fan of goth music, and hates the American education system.
In the alternate universe game Pico's School: Love Conquers All, Pico helps Cassandra and the "Goth Punks" learn to channel their aggression in healthier ways. Pico and Cassandra become friends and she is revealed to be into furry art.
Cassandra has appeared in several games, including Pico vs. Uberkids, the cancelled Pico's School 2, and is confirmed to be an upcoming character in Friday Night Funkin'. She has a cameo during a stage in Newgrounds Rumble.
Cassandra has also appeared in art celebrating Pico Day alongside Newgrounds mascots and other characters from the Pico series like Nene and Darnell.