Chachi Arcola
Charles "Chachi" Arcola is a character played by Scott Baio on the sitcom Happy Days, and its spin-off Joanie Loves Chachi.
The character of Chachi is the younger cousin of Fonzie, first appearing in the television series Happy Days in 1977. He eventually became a "heart throb" and love interest for the character Joanie Cunningham, with their relationship becoming a common theme for episodes.
Chachi and Joanie moved off into the spinoff series Joanie Loves Chachi, when his mother Louisa and new stepfather Alfred "Al" Delvecchio, (the second owner of Arnold's) opened a new restaurant where Joanie and Chachi performed most of their music.
Joanie and Chachi along with some of his cousins and a character named Bingo form a band, which is never named in the series.
Joanie and Chachi returned to Happy Days when Joanie Loves Chachi was cancelled, and in the final Happy Days episode, Joanie and Chachi marry.
Read more about Chachi Arcola: Development and Reception