monster

(noun) an imaginary creature usually having various human and animal parts.

(noun) someone or something that is abnormally large and powerful. Synonyms: giant, goliath, behemoth, colossus.

(noun) a person or animal that is markedly unusual or deformed. Synonyms: freak, monstrosity, lusus naturae.

(noun) a cruel wicked and inhuman person. Synonyms: fiend, devil, demon, ogre.

(noun) (medicine) a grossly malformed and usually nonviable fetus. Synonyms: teras.