eggs. When the eggs hatch, several facehuggers attach themselves to humans trapped in the sacrificial chamber. Chestbursters emerge from the humans and quickly grow into adult Xenomorphs. The humans take possession of the Predator's blasters, and conflict erupts between the Predators, Xenomorphs, and humans. Celtic and Chopper are killed by a Xenomorph, and Weyland buys Lex and Sebastian De Rosa enough time to escape from Scar, giving his life in the process. The two witness Scar kill a facehugger and a Xenomorph before unmasking and marking himself with the acidic blood of the facehugger. After Lex and Sebastian leave, another facehugger attacks Scar. Through translation of the pyramid's hieroglyphs, Lex and Sebastian learn that the Predators have been visiting Earth for thousands of years. They taught the early human civilization how to build pyramids and were worshipped as gods. Every 100 years, they visit Earth to take part in a rite of passage by which several humans sacrifice themselves as hosts for the Xenomorphs, creating the "ultimate prey" for the Predators to hunt. As a fail-safe, if overwhelmed, the Predators would activate a self-destruct device to eliminate the Xenomorphs. They deduce that the Predators lured them into the pyramid to use as a sacrifice. Lex and Sebastian decide that the Predators must be allowed to succeed so that the Xenomorphs do not escape to the surface. Sebastian is captured by a Xenomorph, and Lex returns the blaster to Scar. They are attacked by a Xenomorph, and Lex manages to kill it. Impressed, Scar uses parts of a dead Xenomorph to fashion weapons for Lex, and the two form an alliance. Lex finds Sebastian, who has become the host of a Xenomorph. She mercy kills him, but the Xenomorph Queen is freed from her restraints and, along with the other Xenomorphs, begins pursuing Lex and Scar. Scar detaches and uses a bomb in his wrist module to destroy the pyramid and the remaining Xenomorphs and eggs. Lex and Scar reach the surface, and Scar uses acidic Xenomorph blood to mark Lex with the Xenomorph hunter symbol. However, the Xenomorph Queen reappears and attacks. They defeat the Queen by hooking her chains to a water tank and pushing her over a cliff, so that she sinks to the ocean floor under the tank's weight. Scar is fatally wounded. A Predator spaceship appears, and its crew retrieves its fallen comrade. An elder Predator