Sonny is a hunchbacked Caucasian male, with reddish-brown hair. He wears a green shirt and brown pants, and carries a brown backpack.
Sonny is polite to visitors such as Shaggy Rogers and Scooby-Doo, and he even offers them food. He is a little delusional, as he considers the gargoyle statues under his care to be his pets. This also makes him dangerous, as he saw Danica LeBlake as prey to a supposedly live gargoyle that was haunting Paris, using her (who was actually Daphne Blake in disguise) to get his attention so he could befriend it.
After momentarily frightening Scooby and Shaggy, Sonny quickly welcomed them to his cathedral home, offering them snacks to eat. He then introduced his gargoyles by name, which led him to tell them about a live gargoyle he had heard about. After he left to get some beverages, Shaggy and Scooby were attacked by the live gargoyle Sonny had just told them about.
When the gang set out to capture the gargoyle, Daphne was disguised as her cousin, Danica, for whom Sonny fell. He swung in, grabbing her and taking her up to Notre Dame to make sure the gargoyle got its prey and he would finally have a real gargoyle.
By the next day all was forgiven, and Sonny watched Shaggy make Scooby over to resemble a gargoyle-like statue.
- Sonny Les Matines resembles Quasimodo, the main character in Victor Hugo's novel The Hunchback of Notre Dame.
- His name is a play on "sonnez les matines" ("morning bells are ringing"), a lyric in the French folk song "Frere Jacques". In further reference to this, after Sonny introduces himself to them, Shaggy and Scooby say the next line of the song,"Ding Dong Ding".