First rule of the fight app — don't talk about the fight app. "Rumblr," a pending app idea, is pitching itself as Tinder, but for brawling. Like the dating app, Rumblr users would meet strangers, but instead of hooking up, they'd be swinging right hooks. As bizarre as it sounds, the app's creator claims it's "100% serious," and not a "Fight Club"-style hallucination. "We have raised relatively substantial funding from private American investors and the app is fully developed," the Rumblr team told the Daily News in an email. The beta for the fighting app will be launched on Nov. 9, at 5 p.m. EST, the team said. "Rumblr is an app for recreational fighters to find, meet and fight other brawl enthusiasts nearby," according the app's website. It encourages users to insult their matched opponents with this pro-tip: "tell your match what you don't like about their picture." The fight's location and time is also publicly broadcasted so other users can come and watch the melee, according to the website.