- Now. First clue was... What room can no one enter?
- A mushroom.
— Batman (Adam West), Robin (Burt Ward)
8 seconds sound clip from Batman (1966) - A Riddle a Day Keeps the Riddler Away (S1E11) TV Series.
You can hear this line at 00:11:18 in the Blu-ray version of the movie.
Quote context
[...]
- When the riddles stop, that's when he's ready for his final caper.
- That diamond tiara wasn't what he was really after.
- Right, Robin. But we have two more riddles to tell us what it may be.
- Now. First clue was... What room can no one enter?
- Agreed. Uh, the second one. Read it again.
- Golly, Batman. It doesn't seem to make sense.
- Let's see. If your first answer, a mushroom was correct... Why, that's it. Of course.
- What was it The Riddler said when he threw back the tiara?
[...]