In "Krypto's Three Amazing Transformations, a big chunk of Red Kryptonite crashes on Bizarro World, and Bizarro #1 decides to give it to Krypto, but breaks the time barrier by accident and drops it in the past, where Superman is still a boy. Why so convoluted? Is it to introduce the time barrier so Krypto can then try to retreat into it and have time travel/Red K adventures?! Well, the red rock follows and Krypto is turned into a gynormous red parrot in the days of pirates and of Sinbad - it's a crossover I can't help but think is anachronistic.
Meanwhile, in another story in the same issue... Lana puts a transmitter on Krypto's collar so she can get "psychic scoops" about Superboy's comings and goings.