Basil Elks was a convicted burglar with an undistinguished criminal career. While in prison, he was given the ironic nickname of "Basilisk" due to his real name and his unlikely contrast to the fearsome mythological monster.
After leaving prison, Elks attempted to steal a large gem from a New York City museum, but was caught by a museum guard. The guard's bullet from his gun struck the gem, causing it to explode, which transformed Elks into a superhuman being. Elks then easily overpowered the guard and escaped. Elks learned that the gem was actually the Alpha-Stone, a power object once possessed by the alien race known as the Kree and stolen by a Kree starship crewman. Elks then took it upon himself to find the other such gem, the Omega-Stone, in order to increase his powers.
In the course for his search of the Omega-Stone, Elks clashed with the superheroes known as Spider-Man and the original Captain Marvel. Trying to keep the Omega-Stone out of reach of Elks, Captain Marvel was inadvertently teleported with the stone to the subterranean lair of the villainous Mole Man, who intended to use its energies to power an immense laser-cannon in his attack on the surface world. Several heroes, including the Thing and his teammates, the Fantastic Four, tried to stop the Mole Man, and Elks tried to claim the Omega-Stone for himself, only to be covered by molten lava when the laser-cannon was destroyed.
Unknown to the heroes, however, the Omega-Stone saved Elks by growing in size and enveloping him. Subterranean dwellers eventually found the stone, which somehow released Elks, who now had the powers from both the Alpha-Stone and the Omega-Stone. Elks intended to destroy all civilization by beginning a world-wide volcanic chain reaction from the Savage Land in Antarctica. The Thing battled Elks, who teleported both of them to a volcano he caused to rise in the Hudson River of New York City. The Thing and Spider-Man succeeded in overpowering Elks, whose eye-beams went out of control and trapped himself in the collapsing volcano.
Months later, Elks managed to surface, emerging at the site where the Fantastic Four's new headquarters was being constructed. However, no sooner had Elks appeared than he was ignominiously murdered by the one of the villain-hunting vigilante, Scourge, disguised as a workman.
