Lockjaw is a fictional animal character in the Hey Arnold! TV Series.
Lockjaw is an old, tired, graffiti-covered turtle that lived in the city Aquarium. After Lockjaw was ridiculed by his classmates, Arnold, with his Grandma’s help, stole Lockjaw and released it into the ocean, to live a peaceful life.
In Hey Arnold! The Jungle Movie, Lockjaw is at a ceremony honoring Arnold. It is unknown how he made his way back to Hillwood.