What did you catch?

I had to teach my third graders the english words for various sea creatures. The learned fish, octopus, squid, dolphins, crabs, whales, penquins, sea weed, sea horse, shell, etc. etc.

Then the key sentence was What did you catch? the answer being: I caught.....

Well, at the end of each class the kids have to come up to me, and individually answer the key question.
So imagine my expression when a line of third grade girls continuously responded to the question: "What did you catch?" with... "I caught crabs." Apparently that was the only phrase of the 10 possible phrases that all of them could remember. I figure hey, at least they are learning a sentence that might have double value later on in life.