The episode, What Are Little Girls Made Of?, memorably saw Captain Kirk fighting Lurch from The Addams Family.
Since Lurch is built like a brick shit house, Kirk needed something to even up the fight so he grabs a handy, club-like rock. Except it doesn't look like a rock; it looks like a cock.
Edit. I didn't make the YouTube vid, btw. Some other enterprising chap did that for our amusement.