When I woke up in the morning a few days ago, the first thing I saw through my window was trees and bushes caked in ice. When I took a closer look, I notices that the ice had formed a spiky formation on branches and twigs.
What I heard was that if there is fog on a day in which the temperature is below freezing, you get these cool formations. Fog is made of water droplets. If the temperature is below freezing, the droplets a cooled, allowing them to remain a liquid in the air. After the droplets touched a freezing surface, they froze in that position and shape, creating these formations.