Along with Santa Claus and Krampus, Gryla is an actual myth associated with winter, possibly the oldest one. Of Icelandic origin, Gryla was an ogre with 13 sons, the Yule Lads. Gryla would tour the world on winter nights, asking for charity for her sons. Legend has it that, if she was denied charity, her sons would enter the dwelling and cause mischief until the owner begged Gryla to retrieve them. The idea of shape-shifting abilities and handing out punishment are later additions to the myth, borrowed from the Wild Hunt, another Nordic legend in which a pack of ghost hunters (Odin's entourage) would often give worthless gifts to kind strangers, like a bag of coal or manure. If accepted this worthless gift would turn into gold the next day.

Krampus the demon has been a part of the Yule legend for centuries. He traditionally accompanied St. Nicholas and dispensed lumps of coal or an occasional switching with a stick to the bad children. His night is celebrated on December 5th, the day before St. Nicholas makes his rounds on the 6th. It's a huge, often raucous celebration in many parts of the world, though now done in fun. Eventually, St. Nicholas morphed into Santa Claus in many traditions, but the feast of St. Nicholas, Bishop of Myra, is still an important holiday in Belgium and the Netherlands. Myra is a city in present day Turkey, where Nicholas lived in the 3rd and 4th centuries A.D.

Megaloceros, an extinct deer were used to pull Santa's sleigh. Also known as the "Irish Elk" or "giant deer." The Megaloceros is larger than the common moose. They averaged 6.5-7' tall, 9.10-10.6' long and have antlers about 12' across.

Originally a Prime Video original, but got changed to a theatrical release instead.

Chris Evans dropped out of the film Fly Me to the Moon (2024) with Scarlett Johansson to star in this film. He was later replaced by Channing Tatum.

Factual errors

Cal and Nick leave a mall in Philadelphia, PA and travel to a Air Force Base to depart. However, the Fighter Jets have "TY" Written on their tails, which stand for Tyndall Air Force Base, which is just east of Panama City Beach Florida. This is the F-22 Training Squadron based at Tyndall AFB.

When Cal and Jack step out of the storage of the toy store in Germany, both doorknob and light switch are clearly American. Also, cemeteries are laid out differently in Germany like the one seen in the following scene.