How can I get a mystery creature?

When the tree hole is filled with three plants and the greenhouse is obtained, you will discover a creature coming to visit!

In general, by changing the plant combination in the greenhouse, you have the chance to get different creatures; however, it is also possible to get the same creature with different plant combinations. If that happens, please do not be discouraged, dear gardener. Keep cultivating new plants, change different combinations, and welcome various creatures!