At just 4 months old, this sweet little puppy named Nova is already shaping up to be a world-class guard dog.

You see, nothing gets by Nova — not even threats she’s dreamt up herself.

The other night, at around one in the morning, Nova awoke to find a mysterious intruder had invaded her sleeping spot. And, like a brave watchdog, she sprang into action — alerting her owner, Taylor Eubanks, of the danger at hand.

“I was half asleep when I heard the barking,” Eubanks told The Dodo. “She doesn’t normally bark, so I checked live surveillance

from my phone and saw her staring something down and circling it. I figured it was either a bug or maybe even a snake to give her this much of a spook.”

Naturally, Eubanks sprang out of her room to see what it was that had thrown Nova into such a tizzy. Surely, it had to be something pretty scary to get her dog so worked up.

Here’s video from the surveillance camera, and a closer look at the “monster” Nova had found in her bed:

“When I turned on the lights, there, lifeless on the ground, was a wad of yarn,” Eubanks said. “Nova, herself, pulled it off her blanket that day. I couldn’t help but laugh.”

Even after the “monster” was unmasked, Nova was still on guard.

“She continued to circle it, but braver now that I had arrived,” Eubanks added. “She even booped it with her nose a few times, but still proceeded with the utmost caution.”

It was then that Eubanks stepped in to do what Nova was too afraid to do.

“I took the yarn monster out of her pen to prevent another ‘situation,'” she said. “Things were quiet the rest of the night. Crisis averted. Suspect now in the trash can.”

The house was safe once again.

Chances are, this won’t be the last “monster” scare for a dog as vigilant and imaginative as Nova — but Eubanks will always have her back.

“I forgot how much work it was to have a puppy,” she said. “But it has been 100 percent worth it.”