Sorry that I'm a bit late with this post to clarify this weeks' topic. I somehow thought that last week was the final one for the animal idioms, and I didn't realize otherwise until this morning.
I'll just post a quote from the Wikipedia article on "elephant in the room," as I can't imagine being more clear than this is:
"Elephant in the room" is an English metaphorical idiom for an obvious truth that is either being ignored or going unaddressed. The idiomatic expression also applies to an obvious problem or risk no one wants to discuss.
It is based on the idea that an elephant in a room would be impossible to overlook; thus, people in the room who pretend the elephant is not there have chosen to avoid dealing with the looming big issue.
With this in mind, it would be best NOT to write about an actual elephant in the room. Rather, think of a situation that uses the idiomatic meaning of this expression.