A Common Saying, Cool as a __
This page is the CodyCross answer for the clue below from Space Exploration, Group 912, Puzzle 1 (Aurora Borealis).
Question is: A Common Saying, Cool as a __
and the answer is: CUCUMBER
Word Meaning:
CUCUMBER — A vine in the gourd family, Cucumis sativus.
Definitions from Wiktionary.