Beginning in December 2015, Batman/Teenage Mutant Ninja Turtles is a six-part crossover between Batman and Teenage Mutant Ninja Turtles (IDW), the result of a collaboration between DC Comics and IDW Publishing.The story begins during a battle with Krang, who transports the Turtles, Splinter, the Shredder, and the Foot Clan to an Alternate Universe. Finding themselves in Gotham City, the Turtles meet Batman and clash with his Rogues Gallery while trying to find a way back home.The miniseries is six issues long, and ran from December 2015 to May 2016. The sequel has been announced to launch in December 2017 and end in May 2018, telling a story of Donatello trying to establish a portal between Turtles' and DC Universe but accidentally getting stuck in Gotham....while Bane got to his world.Meanwhile, there's another crossover series called Batman/TMNT Adventures, which teams up the Batman from Batman: The Animated Series with the Turtles from the 2012 Nickelodeon series.Currently under construction.
- 20% More Awesome: At one point, Michelangelo tries to determine whether or not Batman is 40 percent more or less awesome than the Turtles based on his morality.
- Brought Down to Normal: What is slowly happening to the Turtles and Splinter; after analyzing a sample of their blood Batman managed to acquire, Lucius Fox discovers that the mutagen that transformed them is incompatible with the laws of physics in the DC Universe, and thus, they're slowly reverting back to ordinary animals. Part of the plot is the Turtles and Splinter trying to return home before that happens.
- Conspicuous Trenchcoat: After storming out of the Batcave, Raphael briefly dons one of these before Batman pulls up in the Batmobile.
- Crossover: Between Batman and the IDW incarnation of the Turtles.
- I Know Your True Name: Splinter follows Batman to the Batcave and discovers the truth about their impending reversion, as well as Batman's Secret Identity. When he and the Turtles later show up in the Batcave, Splinter is able to convince Batman to help by addressing him as Bruce Wayne.
- Jerkass Realization: Frustrated at their lack of progress in stopping Shredder or finding a way home, Raphael gives Batman a "The Reason You Suck" Speech, outright declaring him to be nothing but "a selfish little rich kid" who beats up bad guys for the fun of it whom he refuses to put his faith in. Raph gets hit with this trope when Batman takes him to Crime Alley, where his parents were gunned down in front of him, and explains how that loss motivates him to do what he does.
- Let's You and Him Fight: The first meeting between the Turtles and Batman results in a fight, mostly due to Raphael.
- Motive Misidentification: Early on, Raphael believes that Batman is just a "selfish little rich kid" who puts on a costume and fights bad guys purely for the thrills and fun of it, until Batman takes him to Crime Alley, where he watched his parents die, and explains that it's that loss that motivates him to be a hero.
- "The Reason You Suck" Speech: Raphael dishes one out to Batman after losing his patience with him, unable to see what his brothers find so cool about him:Raphael: I see right through your dumb cape and cowl, Batman. You want to know what you are? You're just a thrill-seeker. You're some rich guy who puts on a costume and punches bad guys because it seems like fun. You chose this life. We didn't. We became what we needed to become to survive. We fight Shredder because if we didn't, he'd have us all killed in our sleep. But you don't care about any of that, do you? That's why we failed. If we hadn't listened to you, we could have snuck into that base and gotten home by now. Shut the whole thing down from the other side. We wouldn't be stuck here. We wouldn't have this death sentence over our heads. And for some idiotic reason, they can't see that. They think you're the hero you pretend to be. But I see the truth. You're just a selfish little rich kid doing all of this for kicks, and that's not someone I'm going to put my faith in.
- Villain Team-Up: After his first fight with Batman and the Turtles, Shredder ends up joining forces with Ra's al Ghul.
- The sequel has Bane team-up with various Turtles villains like Baxter Stockman or Bebop and Rocksteady.