The Helping Hand is one of many remote-controlled hands created by the Von Gizmo twins.
The New Scooby-Doo Mysteries
It appeared to be a monster to Shaggy Rogers and Scooby-Doo at first, until they learned how to control it. Ratfield, the Von Gizmo twins' ex-assistant, wanted to steal the hands to use for crime. (The Hand of Horror)