Nick Thomas

Nick was Jimmy's tennis trainer and dressed up like Warlcok Anthos because if Jimmy lost the match and the estate he and his brother planned to buy it.

Non-Cannon
In a alternate reality, he wasn't actually the Warlock,and he fused the Harlem Globetrotters into a black dusty pixie. But Shaggy and Scooby, with the help of Blue Falcon, Dynomutt, Fat Albert and the Cosby Kids, Scooby is held by Blue Falcon, with Rudy using his guitar to play with a beam of light dodging Anthos' staff reflecting on Scooby's collar to dodge it to destroy his staff, sending him and Double Hound back to the Shadow Realm.