Andre Norton: Voodoo Planet
A duel of two cosmic magicians - a horrible death for the loser

 A Free Trader space ship visits the planet Khatka where magic and Voodoo are threatening to destroy the promising civilization that has been slowly developing. The medic Tau uses his own knowledge of magic to help fight this evil menace... but is it enough? Can he fight the very powerful Witch Doctor on his own territory? Listen and find out."From between the two shuffling dancers padded something on four feet. The canine-feline creature was more than just a head; it was a loose-limbed, graceful body fully eight feet in length, and the red eyes in the prick-eared head were those of a killer.... Words issued from between those curved fangs, words which Dane might not understand...."Dane slid his blade out surreptitiously, setting its point against the palm of his hand and jabbing painfully; but the terrible creature continued to advance.... There was no blurring of its lines...."Dane Thorson of the space-ship Solar Queen knew there was only one way to win out over this hideous thing—a battle to the end between his rational mind and the hypnotic witchcraft of Lumbrilo, the mental wizard of the planet Khatka.