Zhou Chun wielded the "Golden Rainbow Sword" to slash open the chest and abdomen of the Serpent Lizard Beast, extracting a black Demon Core from within.
This Serpent Lizard Beast counted as a water-attribute Demon Beast, whose attributes did not match any of Zhou Chun's Spirit Pets. Later, he had to either find someone to refine it into an Elixir or wait for an opportunity to exchange it for a metal or earth attribute Demon Core for the Golden Armor Rock Turtle and Golden Winged Tiger to consume after they advanced to the Third Order.
As for a thunder attribute Demon Core, that was too rare to be exchanged for with an ordinary water attribute Demon Core at all.
Furthermore, giving the Demon Core to the Wood Charm, which cultivated incredibly fast, would just be a waste.
After securing the Demon Core, Zhou Chun took apart the beast's skin, teeth, bones, and other materials. However, because the flesh contained poison, he had to abandon it.
