Near Meteor Crater, the HopiS are threatened by a formidable alien predator, half vegetable half animal! The monster has reached earth thanks to seeds or spores transported by a meteorite and looks like a sea urchin topped by a scarlet flower. There is nothing Tex can do but to turn to El Morisco to observe, together with an astonished Eusebio, the incredible capacities of this extraterrestrial: after having killed the predestined victim by striking it with a microscopic poisoned thorn, it attacks and drains all the blood from its victim!