Basil Elks was a convicted burglar with an undistinguished criminal career. One of his fellow prison inmates, who was more erudite than the rest, mocked by Elks by making a pun on his name and calling him "Basilisk," after the mythological creature which could kill with its glance. Other prisoners seized upon the new nickname as a means of ridiculing Elks, thus ironically contrasting the basilisk's fearsome reputation with Elks' own image of being a loser.
After leaving prison, Elks attempted to steal a large gem from a New York City museum. Elks was discovered by a museum guard and reached for his gun, unwilling to return to prison and face further ridicule. The guard fired his own gun, but his bullet struck not Elks but the gem, causing it to explode. Unknown to Elks and the museum authorities, the gem was actually the so-called Alpha-Stone, a power object once possessed by the alien Kree. A Kree starship crewman had stolen both the Alpha-Stone and another such gem, the Omega-Stone, and escaped in a small spaceship, which exploded; somehow the two gems ended up on Earth. The explosion of the Alpha-Stone transformed Elks into a superhuman being, who overpowered the guard and escaped. Elks adopted the name "Basilisk" as one that was appropriate to his newfound powers, and sought the Omega-Stone in order to increase them. In the course of his search, the Basilisk clashed with both Spider-Man and the Kree Captain Mar-Vell. The Omega-Stone was embedded underground in the Wall Street area of lower Manhattan. Mar-Vell found the gem, but when he touched it, the gem grew to gigantic size and enveloped him.
The enlarged Omega-Stone was then teleported to the underground domain of the Mole Man, who intended to use its energies to power the immense laser-cannon he planned to use to attack the surface world. Spider-Man and Mister Fantastic opposed the Mole Man, but Basilisk, arrived at the scene, and Captain Mar-Vell freed himself from the Omega-Stone, which returned to its previous size. The laser cannon malfunctioned, causing magma pits to erupt. When the Basilisk reached for the Omega-Stone, he was covered by molten lava.