Boney is Lucas' pet dog, staying with him as his friend even after Claus left and his mother died. He accompanies Lucas in combat as one of his party members, with his main ability being that he can sniff out an enemy's weakness.
Boney appears as a sticker in Brawl.
Boney, along with Kumatora, accompany Lucas when he uses PK Starstorm in Super Smash Bros. Ultimate. Lucas also retains his alternate costume depicting Boney on his t-shirt. Boney also appears as a spirit.