Lenny Fiasco was a college classmate of Bruce Wayne (Batman), and was continually mocked by his fellow students for all the mistakes he made in class. The few people who remembered Lenny always pictured him with eraser in hand, correcting his mistakes. The only girl Lenny ever wanted was fellow classmate Celia Smith, and he planned to take her to the school's ice carnival. Lenny was crushed when she chose to go with Bruce Wayne. Feeling quite bitter, he turned to a life of crime, developing an eraser costume that could eliminate all evidence from a crime scene.
He took out advertisements as the Eraser in The Secret Underground, a periodical aimed at Gotham's small-time criminals. For a twenty percent commission, before taxes, the Eraser offered to remove all clues at a crime scene before a police investigation could be conducted: "Don't take chances! Let the 'Eraser' erase every clue from your crimes! Only 20% of job--before taxes! Write to ...General Delivery!" In his suit and full head mask, the Eraser resembled a living number two pencil. He did a commendable job, and the police were baffled at the lack of clues at a series of bank robberies.
They called on Batman, who disguised himself as an organ grinder and hired the Eraser for a mock robbery. Eraser then removed his mask, showing how the eraser helmet mounted on it was treated with a special compound that removes everything--even the almost invisible impressions made by the soles of shoes. Eraser recognized Bruce Wayne through the disguise, explaining that for years he hat sat next to Bruce attending college classes, smelling the special shaving lather he used, and he was able to recall the smell when he sniffed it again. Placing a hand on Bruce's shoulder, Lenny revealed that he confirmed ' identity because an individual's skin acid makes any shaving later he used react differently than someone else's. The villain then told Bruce that he had became a criminal because Bruce shattered his dreams of going out with Celia Smith. Bruce didn't even remember Celia's name, prompting Eraser into a rage. He knocked Bruce out with sleeping gas, and Bruce awoke at Eraser's headquarters, where the Eraser had constructed a recreation of the college ice carnival. Robin then arrived on the scene and distracted Eraser long enough for Bruce to change into his Batman identity. What followed was academic, Batman beat up Eraser and sent him to jail. In jail Batman presented Fiasco with a giant eraser, and advised him to make a new start in life with a clean slate. Lenny didn't seem too amused with Batman's joke.
This issue (Batman #188) is widely acknowledged as the nadir of Batman comics history.
The Eraser has made minor cameo appearances in Post-Crisis continuity, though never as a major villain. He first turned up in Ambush Bug: Year None #4 (2008).
Lenny Fiasco as the Eraser later returned as part of Bruce Wayne's imagination in Batman: RIP. The Eraser also recently appeared in Neil Gaiman's 2009 story " Whatever Happened to the Caped Crusader?" which shows the effects of Batman's death on his enemies and allies.
Powers and Abilities
The Eraser wore shoes tipped with pencil-point blades that could also emit a sleeping gas. He wore a mask topped off with a giant eraser that could rub out evidence from crime scenes like footprints, fingerprints, etc.
In Other Media
Batman: The Brave and the Bold
The Eraser makes a cameo appearance in the Batman: The Brave and the Bold episode "A Bat Divided!" where he was drinking with other Batman villains in the "8 Bar", a known haunt for third-rate costumed villains before a Batman showed up to beat everyone there up. He later makes a cameo in "Joker: The Vile and the Villainous" where he was seen at the bar where the bad guys hang out.