The Secret of the Sinister Abyss
Inexplicably, Aquaman's pet octopus, Topo, kidnaps his infant son, Arthur, Jr., while Aquaman is tending to Mera, in another part of the Aquacave. Aquaman's pursuit of Topo is halted, when the Sea King is suddenly entangled by a mutant strain of staghorn coral. It takes incredible effort for Aquaman to uproot the clinging organism, and garner his freedom. Following Topo deeper into the submarine canyon, Aquaman finds the octopus locked in combat with a gigantic crab. Aquaman attacks the massive crustacean, giving Topo time to collect Arthur, Jr, and carry the boy away from the danger. With Aquaman caught in one of the crab's monstrous pincers, he is helpless to pursue Topo. Meanwhile, at the opposite end of the cavern, a group of Idylists are ambushed by a malevolent creature, that quickly enslaves them. Aquaman telepathically summons several moray eels, commanding them to form a chain around the crab's rear legs, and pull it off balance. Freed, Aquaman then impales the crab with a jagged piece of wood. Reaching the end of submarine canyon, Aquaman encounters Starro, the enslaver of the Idylists, and an old foe of the Justice League of America.
This Starro, however, is not the one defeated years ago by the Justice League of America. Anticipating it's possible destruction, that Starro left a piece of itself in the ocean, to regenerate the creature, should it meet its demise. Due to unforeseen circumstances, the regeneration process stalled. It only reached it's full culmination due to the concentration of pollutants fouling the waters of the submarine canyon. The same chemicals that mutated the marine life, in submarine canyon, also boosted Starro's mental abilities, allowing it to telepathically enslave others, such as the Idylists. Starro commands the Idylists to attack Aquaman. Aquaman quickly defeats Starro's mind controlled slaves, then telepathically summons a vast armada of porcupine fish. The porcupine fish begin spraying Starro down with water. As the porcupine fish have come from outside the submarine canyon, the water they are carrying is untainted by the chemicals that give Starro it's strength. Starro quickly loses it's powers, then suffers a serious beating at the hands of Aquaman. Contacting his comrades in the Justice League of America, Aquaman turns the defeated "conqueror" over to the Green Lantern for disposal. By chance, the Idylists are, in fact, looking for Aquaman. A great peril has befallen Aqualad, and the Idylists have come to enlist Aquaman's aid in saving their hero.
J'onn J'onzz, the Manhunter From Mars, has come to Earth in search of the murderer of his old friend, R'es Eda. N'or C'ott, the commander of the Martian army has followed J'onzz, intent on bringing the Martian Manhunter back to Mars II, for treasonable acts. As his comrades in the Justice League of America are the only Earth men who knew of the existence of the Martian colony, on Mars II, J'onzz believes Eda's murderer must be one of his old friends. J'onzz approaches a Thanagarian police ship, in low orbit over Earth. He is welcomed onboard by Hawkman and Hawkgirl. J'onzz immediately attacks, striking Hawkman down, then slamming Hawkgirl into the wall. Pressing his assault on Hawkman, the fight carries them outside the ship. J'onzz beats Hawkman into unconsciousness, before succumbing to the vacuum of space. Hawkgirl races out of the ship to rescue the two heroes. Realizing that the Thanagarians are not going to do his dirty work for him, C'ott loads an incendiary bomb into the chest cavity of a Superman robot, and sends it over to Hawkman's ship. Hawkman replays the ship's log for J'onzz, which proves the Thanagarians were not on Mars II, when Eda was killed. At that point, the robot boards the ship. Mistaken for the real Superman, none of the three heroes suspect the terrible danger the robot presents.