"Challenge of the Cardboard Criminal!"
*It's not often that Barry Allen finds himself trapped between two problems. His first problem arises in the form of a woman from his past, who is suffering from amnesia. The second proves to be the more deadly of the two, a new super-villain who seems impossible for the Flash to defeat. Unknown to Barry Allen, the villain seems to have been created from the mind of Barry Allen's young next door neighbor, artist Barney Sands! *Source: DocRx8482
Note: This story runs from issue #248-250.