Gotham's greatest heroes, Batman, Robin, Batgirl, and Nightwing, are all known for their shocking stealth. One of Batman's greatest strengths is the mystique that surrounds him, inspiring fear in his enemies. Batman's ability to sneak became such a mythical symbol in Gotham that even criminals can hardly believe it's Batman when he descends upon them. This is only made possible through his ability to hide in the shadows, waiting for the right moment to strike before disappearing as swiftly as he came. However, there are some mysteries to Batman that aren't quite as enviable when his secrets are revealed.
The first Robin, Dick Grayson, trained with Batman from a young age and learned many of his tactics from the Dark Knight himself. From the cheesy shark-repellant of the 60s to his iconic batarangs, Batman seems to have a gadget or resource for every situation. Even after Nightwing strikes out on his own in Blüdhaven, attempting to create a new life for himself separate from Batman, there are some tricks he can't leave behind. One of these handy strategies allows the former Boy Wonder to silently evade the wrath of guard dogs.
In Nightwing #111, by Devin Grayson and Cliff Chiang, Dick Grayson sneaks into Rand Westbrook's home to glean information about Deathstroke. Despite Westbrook owning a guard dog, Nightwing sneaks in undetected. It's not until Westbrook comments on Nightwing's potent scent that Dick reveals his secret—bear urine. Grayson explains that while he'd love to befriend Westbrook's dog, he doesn't have time. The urine is enough of a deterrent for Nightwing to get what he wants. Unfortunately for his human victims, it's an unpleasant stench to encounter late at night.
While bear urine is commonplace in people's yards as a dog repellant, taking advantage of their fear of bears, it's unlikely that most would even consider using it as a perfume. However, this is a Batman play from head to toe. Rather than trying to create a new formula of his own or use a high-tech gadget, Batman takes the more resourceful route. It's this strategic thinking that makes many fans believe Batman is a genius. Unfortunately, this information strongly suggests that when sneaking around places where they expect to encounter dogs, the Bat-Family habitually smells of bear urine as a speedy workaround. It certainly isn't the coolest secret to their legendary stealth.
Despite being dubbed one of the most attractive men in the DC Universe, it's likely that Nightwing regularly smells of bear urine. Hopefully, he showers thoroughly before dates. Even though Batman and Nightwing have had a tumultuous relationship at times, they'll always be bonded through their shared experiences—and ridiculous crimefighting methods. When it comes to stopping crime, the Bat-Family really will do whatever it takes as proven by Nightwing, sacrificing dignity and hygiene in the name of justice.