Over a dozen people were hurt when a knife-wielding man wearing a Joker-like costume attacked riders on a crowded train. SUBSCRIBE to GMA's YouTube page: https://bit.ly/2Zq0dU5 VISIT GMA's homepage: https://www.goodmorningamerica.com SIGN UP to get the daily GMA Wake-Up Newsletter: https://gma.abc/2Vzcd5j FOLLOW GMA: TikTok: https://tiktok.com/@gma Facebook: https://facebook.com/GoodMorningAmerica Twitter: https://twitter.com/gma Instagram: https://instagram.com/GoodMorningAmerica #GMA #Tokyo #TokyoSubway #Joker