The legend of mistletoe 

This legend talks about the Goddess Frigga, the Goddess of love and her son Balder, the God of summer sun.
One day Balder dreamt of his death and told his mother about the dream. Frigga was very worried for her son but also for the life on Earth because without Balder the life on Earth will be over.
So Frigga asked for help to every being in air, water, fire and earth to promise her that they will never hurt her son. But Loki, the God of evil knew that Frigga forgot a plant, the mistletoe.
So Loki made an arrow and put a spring of this plant on the tip. Then he deceived his blind brother and he pulled the arrow in the face and Balder immediately died. But Balder was revived only by Frigga. Her tears on the plant become white berries and she blessed it and when someone was under the mistletoe would never be harmed and they had to give a kiss.