Brave and the Bold (1955 1st Series) #68

Cover pencils by Mike Sekowsky, inks by Joe Giella. "Alias the Bat-Hulk," script by Bob Haney, pencils by Mike Sekowsky, inks by Mike Esposito

When the Riddler, Joker and Penguin team up together to commit a series of crimes to grab Batman's attention, he falls into their trap which leads to Batman being exposed to a chemical of the Joker's design that causes Batman to periodically change into a creature dubbed "Bat-Hulk", a giant muscle-bound creature who's touch can melt anything in its grasp; Changing back to human form, Batman seeks out the aid of Metamorpho to try and find a chemical combination to reverse the mutation, however Batman changes back into Bat-Hulk and goes on a rampage, before ultimately finding the Joker, Riddler, and Penguin and joining up with them in their next criminal plot; Metamorpho goes after the crooks, and battles the Bat-Hulk, clearly a Hulk parody. 

36 Pages, Full Color. Cover price $0.12.