The Atom-Master!
A mad scientist of sorts, who with the use of his special helmet, is able to rearrange the dust in the air and materialize it any form he desires.
His original crime spree was cut short by Superman, Batman, and Robin, but never count on a renegade scientist to stay idle for too long. Unfortunately for him, his return to the big time years later was as a member of the Forgotten Villains! And true to form, he has remained forgotten to this day.
He did have a redemption of sorts, turning against the Enchantress at the last moment to prevent her from taking over the world. I think he should count himself lucky, as it's rare for a character that continuity forgot to have a relatively complete and satisfactory storyarc.
If you can call three appearances over 25 years a storyarc.
UPDATE: And yes, for those of you keeping score at home, this is the same Atom-Master who created the illusion of the T-Rex from the last Sunday versus post.
Script by Marv Wolfman
Pencils by Curt Swan
Inks by Dave Hunt
Colors by Gene D'Angelo
Letters by Ben Oda
DC Comics Presents #77
Triad of Terror!
January 1985
Copyright (c) DC Comics
Pencils by Curt Swan
Inks by Dave Hunt
Colors by Gene D'Angelo
Letters by Ben Oda
DC Comics Presents #77
Triad of Terror!
January 1985
Copyright (c) DC Comics