Last year, the death of Alfred Pennyworth rocked Batman's world in a major way. While Bruce Wayne and the rest of the Bat-Family are still grieving Alfred and learning how to live without him, it's not the first time that they've had to deal with the loss of the ever-reliable butler.
When editor Julius Schwartz took over Batman in 1964, he did away with several of the sillier aspects of the series, including original Batwoman and Bat-Girl. And in Bill Finger, Sheldon Moldoff and Joe Giella's Detective Comics #328, Alfred was killed off to make room for Dick Grayson's Aunt Harriet as the Dynamic Duo's caretaker. While Alfred died heroically saving Batman and Robin from a giant boulder, Alfred was revived by a mad scientist named Brandon Crawford, and he was resurrected as the villainous Outsider in Detective Comics #366, by Gardner Fox and Sheldon Moldoff.
When Dr. Crawford used experimental radiation treatment on the discovered body of Alfred, he revived Alfred but unlocked a sinister alter ego. The Outsider woke up with a powder-white stone-like body and telekinetic powers. He had absolutely no connection to his previous Alfred Pennyworth identity and had a singular desire to kill Batman and Robin, those he held responsible for his death.
After causing havoc around Gotham, he went on to team up with Blockbuster and the Grasshopper Gang in his tireless crusade to eliminate the Dynamic Duo. He would use gimmicks to deliver threats and messages to Bruce Wayne and Dick Grayson, showing that he still knew their secret identities, even if he had no connection to his previous life. When he continued to be unsuccessful in his mission, he turned to chemical warfare and attempted to create a chemical reaction that would turn all of Batman and Robin's nifty gadgets against them.
Batman learned the true identity of the Outsider and went on his own crusade to save Alfred from his evil alter ego. Spurred on by the guilt he felt over not finding Alfred's body after the accident, Batman went on to capture the Outsider and paid for an expensive radiation treatment that restored Alfred to his old self.
Once The Outsider was no more, Alfred had no memory of his criminal past and returned to his butler duties at Wayne Manor. On a few occasions, Alfred would slip back into the Outsider identity and face-off against the Dynamic Duo, but that stopped after Crisis on Infinite Earths.
While a different Outsider appeared in the Flashpoint reality, this character was a metahuman named Michael Desai, who calls himself the Outsider because he thinks he doesn't fit in society due to his genetic enhancements.
In the New 52, another Alfred Pennyworth returned as the Outsider during the Forever Evil storyline. This character was really the evil Alfred Pennyworth from Earth-3. He made his way over to the DC Universe when a Justice League battle with Darkseid weakened the barrier between the worlds. Although he was supposed to travel through with Owlman --Earth-3's villainous Batman -- they were unable to cross together, so the Outsider made plans to recruit enemies of the Justice League to build the Secret Society before he was ultimately killed by Black Manta.
Even though Alfred is currently dead in the DC Universe, he will almost certainly return at some point. But if his history as the Outsider is any indication, he might not be the trusted Batman ally that he was when he perished.