A bunch of little terrors will set out to destroy the Christmas spirit in Portland in the next all-new episode of NBC's "Grimm" on Friday.

NBC released two preview videos of the upcoming episode, which is titled "The Grimm Who Stole Christmas."

In one preview, Monroe surprises his new wife with a cute note inviting her on a honeymoon vacation. However, as soon as she agrees to go, a toy train falls off the track. Although the newlyweds try to disregard it as an omen, it seems safe to assume that the sign is indeed one.

Another teaser video reveals that a threesome of little Wesen known as Kallikantzaroiis will haunt the residents of Portland while trying to ruin all festivities and seasonal decorations.

The gremlin-like creatures eventually make their way into Rosalee's home while she and her best friend Juliette are the only people home. The women try to keep the mini-Wesen from entering their home, but they manage to break in and go straight Rosalee's beloved Marklin train. That's when the women use several household objects, including vases, frying pans, and antique nutcrackers, to stop them.

Meanwhile, the men try to identify the hairy beasts at Nick's trailer, and Trubel goes on a mission to find out who has been harassing the mixed-breed newlyweds.

According to actor Silas Weir Mitchell, Monroe and Rosalee's first Christmas as a married couple will be unforgetable.

"Boy, it's a great episode," he recently told Zap2it. "The storyline is great, the creatures -- it's a good one. I'm excited"

According to Dread Central, the official synopsis for "The Grimm Who Stole Christmas" reads as follows:

"Nick (David Giuntoli) and Hank (Russell Hornsby) are called to investigate a bizarre string of home invasions that lead to an even stranger Wesen phenomena. Monroe (Silas Weir Mitchell) has a very special Christmas surprise in store for Rosalee (Bree Turner).

"Meanwhile, Truble (guest star Jacqueline Toboni) comes to a life changing realization that will affect everyone. Bitsie Tulloch, Sasha Roiz, and Reggie Lee also star."

Season 4 Episode 7 of "Grimm," " The Grimm Who Stole Christmas," premieres on NBC on Friday, Dec. 5, at 9 p.m. ET.

Watch the teaser videos below.

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