"My Friend Nigel" by Jo Hodgkinson

While mom and dad are doing magic and tricks, their little boy is not interested in anything but saving Nigel the snail from being part of their potions. His determination to be best friends with Nigel confuses his parents who conjure up various animals they feel are more appropriate for him. However when their magic backfires, it's Nigel to the rescue teaching the parents that the magic of friendship is very special indeed. Kids loved the slime trail Nigel leaves behind him in the book.