The term SCI-FI BEASTIE is a combination of two words, 'sci-fi' and 'BEASTIE, ' which refer to a type of creature found in science fiction stories. The crossword solution for this term is MUTANT, which is a creature that has been altered from its original form through genetic mutation. Mutants are often found in sci-fi stories as powerful or dangerous creatures, and they can be either human or animal in origin.