Justice League of America #91

Three aliens are out on a joyride alongside their symbiotic pets when they lose control of their ship, resulting in the alien A-Rym being separated from his pet as they travel through the dimensional barrier separating Earths 1 and 2. As the JSA face off against A-Rym, he defeats them, as a result of the adult Robin charging in headstrong. Meanwhile, on Earth-1, as Batman leaves the JLA for another case he's working on, young college-aged Robin faces off alongside the team vs. Teppy, A-Rym's symbiotic pet, with the same actions and consequences. To be continued...