Solar Boy? Is he the boy version of Solar Man? If you like.
This one begins with Krypto mischievously blowing shells around at a naval firing range.
You see, in an untold tale, Solar Boy had come to Earth to steal zoo animals for his private game reserve and was stopped by Superboy and Krypto. Krypto just doesn't remember because he's selectively dumb in this (and every) story. This is Solar Boy's revenge: Make the dog think he's a good master then torture him by denying food and other mean tricks: