He supposedly issued a stern reprimand to a misbehaving student: "You have hissed all my mystery lectures. You have tasted two worms. Pack up your rags and bugs, and leave immediately by the town drain!"
You can read two great articles about it, with lots of examples and much more detailed stories about Dr. Spooner: http://www.fun-with-words.com/spoon_history.html and http://www.straightdope.com/columns/read/2010/who-was-dr-spooner-of-spoonerism-fame.
Do take a look, they are quite hilarious (and informative)!