Detective Comics Vol. 1 (1937-2011; 2016-Variant Covers) #1026

Plot

As "The Joker War" rages on, the casualties are mounting, and the underground residents of Gotham City must deal with the devastating effects of the Joker toxin that's been pumped into the old city's tunnel system. Batman must risk everything to guide them to safety, but a familiar face has mobilized these forgotten souls to rise up in anger...and Killer Croc takes no prisoners!