It’s an unexpectedly dark tale of jealousy and murder.

It happens in every Christmas rom-com: After a couple of rounds of will-they-or-won’t-they, the couple ends up under the mistletoe, sealing their happily-ever-after with a yuletide kiss.

But it turns out mistletoe’s history isn’t so sweet and romantic.

A story of murder and intrigue

Elixir of Knowledge

The story of mistletoe actually begins with jealousy and murder in Norse mythology. The story circles around Baldur, the son of Odin and Frigg, who was beloved but prophesied to die. Baldur became so paranoid about his own death that his mother, Frigg, the goddess of love, called upon every plant and animal in the world to swear an oath that they would not harm her son.

The oath protected Baldur from attacks by other gods who were jealous of his immortality, but the god Loki discovered that Frigg hadn’t gotten an oath from the lowly mistletoe plant because it seemed too harmless. Jealous Loki crafted a spear from mistletoe branches and pierced Baldur through the heart.

Odin begged the gods of death to revive his beloved son. When Baldur came back to life, Frigg was so overcome with joy that she declared mistletoe a symbol of love and vowed to kiss all those who passed beneath it.

From mythology to tradition

Hulu

Exactly when people started to hang mistletoe in their own homes is a bit of a mystery, but we know it began in England. Servants would hang a sprig in a doorway and were allowed to “steal a kiss” under it. Each time someone kissed under the mistletoe, they plucked a berry from the plant; when all the berries were gone, the kissing was over.

Its dramatic Norse history isn’t the only thing about mistletoe that’s a little, er…off. There’s also the not-so-sweet fact that mistletoe berries are poisonous to humans. Oh, and the word itself comes from the Anglo-Saxon words mistel (which means dung) and tan (which means stick). So if you can get over the jealous, murder-filled history of “poop on a stick,” go ahead and pucker up.