The Boy Who Was Followed Home
By Margaret Mahy.
Description
When a hippo follows Robert home one day, he is delighted. Understandably his parents are not. Then more and more hippos begin to crowd into the garden and they are obliged to seek the help of a witch. Her solution is to give Robert an anti-hippo pill, which has some surprising results. - from Amzon
ISBN(s)
080370903X, 9780803709034