He has cancer, and the tumor causes his body to grow at an alarming rate.
Norman Bridwell's creation Clifford the big Red Dog's first appearance was in the 1963 book Clifford, the Big Red Dog.
The book series was written by Norman Bridwell. I believe he also illustrated the books, but I'm not certain. The television series is based on the books.
september 5 1963
That's an easy answer. All the love Elizabeth had for him made him grow big and strong.
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