It appears that this mulberry tree has formed a lovely yellow frost flower, likely because of coloring from the sap inside the branch. This tree is located in the back yard at my son's house in Nashville, and I noticed this lovely ice formation early one morning from the kitchen window. At first glance it looked like a small furry animal resting atop the tree branch.
To find frost flowers be sure to look for them in the early morning hours, but if you find one don't pick it up. These intricate flowers are so fragile they will shatter on touch, so just take some pictures.
My lovely frost flower was so delicate the afternoon warmth melted it away. By mid-afternoon this photo shows all that was left of mother nature's work.