He rushed experiments in an effort to show his intellect again, but was caught in an explosion with the Still Force and had his age accelerated, making him an old man.
Razar, now named the Changeling by the local papers, decided to foil Hull's hijack of a sunken ship recovery operation and then kill him.
Razar dove into the water as Hull's boat left the pier and transformed himself into a large shark.
Deciding that he would need to kill the villain to stop him, the Flash battered the shark's gills until it could not breathe and then knocked it unconscious as the Changeling tried to change forms.
The current incarnation of the Rogues includes Captain Cold, the Weather Wizard, Heat Wave, the third Mirror Master, and the second Trickster.
In chronological order (with issue and date of first appearance): In addition to the Silver Age Rogues, there have been many other Flash villains created in the past few years.