Someone thought Smilex, the name of the gas Joker used to kill Gotham citizens, would be a good name for an electric toothbrush. It could be the last toothbrush you ever use, but at least your smile will be bright and wide. (Source)

Tim Burton was criticized for not having enough Batman in Batman. But fans with a keen eye and good math skills calculated the percentage of screen time that Bruce Wayne is snugly tucked inside his Batsuit. The verdict? Tim Burton's Batman has the most bat-time out of all the Batman movies (Batmen movies?), including the Christopher Nolan films. (Source)

Another group of eagle-eyed fans with keen timekeeping skills timed Joker's ascent of Gotham Cathedral. He tells his men to arrive in ten minutes. How long does it take them to arrive? Ten minutes. Man, do these fans watch movies with stopwatches at the ready? (Source)

Would a bat by any other name smell as sweet? Actually, we don't want to know what a bat—or Batman—smells like. But we would be curious to slip into a parallel universe where another actor was considered for the part of Batman. Other actors rumored to be in contention for the starring bat role in 1989 included Alec Baldwin, Pierce Brosnan, Bill Murray, and Charlie Sheen. (Source)

Speaking of casting rumors, Blade Runner co-star Sean Young was cast as Vicki Vale, but had to drop out due to an injury. Later, Sean Young would break onto the Warner Bros. set dressed as Catwoman, believing that she would be a better fit for the role in Tim Burton's Batman Returns than Michelle Pfeiffer. (Source)

Billy Dee Williams isn't some Rando Calrissian who wandered in off the streets. He was a big-name actor at the time, so why is he only in Batman briefly? Well, his character, Harvey Dent, later becomes Batman's nemesis Two-Face. By the time Batman Forever rolled around, and Tim Burton was replaced by Joel Schumacher, the role was recast with Tommy Lee Jones. (Source)