I’m thinking this book would have come out in the 70s or early 80s. The general plot, as I recall, was a friendly purple creature was friends with a young boy, and the creature had a seemingly magic yellow umbrella. The umbrella was used in a variety of helpful ways, culminating in the umbrella being used as a big swimming pool for all of the neighborhood children. Those are the primary details I remember; any help much appreciated!
Could be Monster and the Magic Umbrella by Ellen Blance, illustrations by Quentin Blake
https://www.goodreads.com/book/show/1863733.Monster_and_the_Magic_Umbrella
YES! That’s the one! Solved thank you 🙂
Thank you so much, my sisters and I have been trying to find these books for years.