From: Superboy #117 (December 1964)
A second super-pupper from Krypton? Stay a while, I will be faithful... Our story starts when Krypto decides to get Superboy's attention while the Teen of Steel is, as you do, carving a giant arrow in a mountain top to help planes find Smallville's new airport. Don't worry, this will have NOTHING to do with the story, nor will his cape's apparent elasticity.
Well, okay, let's go play a game of hot or cold with our non-verbal dog to find out what he wants. Pet owners will likely recognize themselves here.
You want the Phantom Zone projector, boy? Why? Did you perchance telepathically speak with another dog in the Zone? Why yes, yes you did! Who's a good boy! It's you, yes you are!
Also, another nearly identical dog, but for the black patch on his back. Let's call him Spot and let the two them play together. What could it harm? Except an ecosystem, I mean.
But where did Spot come from? There were no criminal dogs on Krypton, and Superboy's eiditic memory has no recollection of him. Not that he would necessarily have a mental catalog of every dog on the planet, but Krypto sure does seem to know him. Only one way to find out: Jump in the time stream and observe events in Krypton's past. And lo and behold, there's Spot at Jor-El's side.
So now we know how the dog wound up in the Phantom Zone, but if he was part of the El household, why doesn't Superboy remember him? Before we answer, Superboy turns his head and sees present-day Earth, where the dogs have gotten into trouble.
So is Spot NOT Kryptonian? Why isn't he affected by Green Kryptonite? What kind of Silver Age double-cross is this? Turn your head again, Superboy, so we can look even further into the past! And he does, and he sees poor Krypto get sent into space, and his baby self crying up a storm, and Jor-El build a robot dog to replace him so he can stop the infernal screaming. But oops!
That's right, Spot is a robot Krypto with a singed back. And baby Kal-El didn't notice a difference, so his memories of Krypto in that era may or may not be those of his actual dog. Disturbing. So now he has his two childhood pets back, right? Wrong. Turn your head to the present again, SB.
Yep, the story didn't want us to see that Spot indeed didn't make it when he crashed through that kryptonite boulder. Cue dog tears.
But WAIT! If this was a robot, how DID Krypto use "canine telepathy" to contact it inside the Phantom Zone? Damn you, Silver Age! You don't play fair!!!
Comments
Also, given that Superboy had a great deal of expertise in making robot duplicates of himself by this time, one has to wonder why he didn't just repair the Dog-bot?
And hey -- if Spot wasn't made of Kryptonian materials, how did he get superpowers in the first place? (The Superboy robots were specifically designed to mimic Kryptonian powers, but Jor-El had no reason to engineer Spot that way.)
And certainly if his construction was tough enough to tunnel beneath the earth at flying speeds, hitting one lousy meteor shouldn't have damaged him that much. This story has more holes in it than The Albert Hall.