The next episode of "Grimm" season 5 very aptly titled "Rat King," Portland will be visited by a gargantuan rat. The monstrous rodent is the latest to wreak havoc in the city and probably the biggest and most intimidating one to date.

Three Wesen come across the murderous giant rat at a local dump, with two of them ending up dead and the other lucky enough to live and tell the tale and warn everyone about the new monstrous being about to terrorize the land.

In the promo, the new baddie around is described as a 20-foot tall ratzilla but no one would believe a creature that sounds like it came right out of a tale of fiction existed until Nick's group lay eyes on the monster that's the size of a house. Needless to say, the new troublemaker in town won't be very easy to beat.

For starters, the mythical creature likes to be called the Rat King and as the synopsis for the "Grimm" season 5 episode teases, it killed two people and it is bound to murder more. Hank downright says in the promo that he hates rats, the regular-sized ones. Nick, on the other hand, dwells on the problem of finding a very big trap for it.

In "Rat King," viewers will also get to check back in on Trubel, who isn't at all in good shape making her return. It remains a mystery how Nick's protégé was able to locate his and Adalind's hideout but it looks like their hidey-hole is no longer safe to stay in especially with baby Kelly growing up fast.

As "Grimm" season 5 progresses, it slowly becomes extra difficult for him to adjust to family life with what he's after and what's after him. In the upcoming episode, things are about to get more ominous, with Nick and Meisner finally coming face to face.

"Grimm" season 5 episode 5 airs Dec. 4 on NBC.