Remember the good old days when phones came with a powerful xenon flash instead of just LEDs? Well, thanks to ASUS, you'll soon have the option to add one to an Android phone -- or at least to an ASUS one, anyway. The ZenFlash came to us as a surprise announcement at today's ZenFone 2 launch in Taiwan: It's a xenon flash dongle that connects via USB OTG, and you can stick it onto the back of your phone for that "400 times" stronger flash. Alas, it's still early days so there's no further detail on this device. No price, no date and no confirmation on whether the ZenFlash will work on non-ASUS Android phones.