Clue: Huge creature found in shell of bizarre male insect? (8)
Answer: BEHEMOTH
Explanation: Definition: Huge creature
B[izarr]E + HE MOTH. It's the Old Testament again: Behemoth is mentioned once in the book of Job chapter 40, and is taken by some creationists (in the 11 across?) as evidence that dinosaurs lived at the same time human beings (and they also think Job is factual, instead of poetic fiction)