A super-heroic crimefighter from the distant planet Trombus, who possesses superhuman powers nearly equal to those of Superboy. Hyperboy, whose secret identity is Kirk Quentin, is the super-intelligent leader of a supergroup known as the Hyper-Family, which is made up of himself, his father Hyperman, his mother Hyperwoman, and Klypso the Hyperdog. Hyperboy, like the other members of the Hyper-Family, only possesses superhuman powers under a red sun and is powerless under a yellow sun, the exact reverse of Superboy.
The Hyper-Family, under Hyperboy's direction, use Superboy to test whether or not their super-suits are completely indestructible and their susceptibility to mind control (SB No. 144, Jan 1968: "Superboy's Lost Identity!").
Note: Hyperboy should not be confused with Hyper-Boy, the teenaged protector of the distant planet Oceania, who later encounters Superman in his adult identity of Hyper-Man (Act No. 265/1, Jun 1960: "The 'Superman' from Outer Space").