mon·ster

– noun
1. a legendary animal combining features of animal and human form or having the forms of various animals in combination, as a centaur, griffin, or sphinx.
2. any creature so ugly or monstrous as to frighten people.
3. any animal or human grotesquely deviating from the normal shape, behavior, or character.
4. a person who excites horror by wickedness, cruelty, etc.
5. any animal or thing huge in size.
6. a. an animal or plant of abnormal form or structure, as from marked malformation or the absence of certain parts or organs.
b. a grossly anomalous fetus or infant, esp. one that is not viable.
7. anything unnatural.
–adj.
8. huge; enormous.

chi·me·ra

– noun
1. a mythological, fire-breathing monster, commonly represented with a lion's head, a goat's body, and a serpent's tail.
2. any similarly grotesque monster having disparate parts, esp. as depicted in decorative art.
3. a horrible or unreal creature of the imagination; a vain or idle fancy.
4. an organism composed of two or more genetically distinct tissues, as an organism that is partly male and partly female, or an artificially produced individual having tissues of several species.