Houston, Texas - "Wait – is she for real?" This question seems to be going through the former stray dog's mind, as he is invited inside a house for the first time ever.

"Buddy, come inside. You're a house dog," his foster mom Samantha Zimmer calls out repeatedly as the pit bull mix looks at her in confusion.

Over and over again he lifts his front paw, only to quickly withdraw it seconds later.

He then sits down in front of the door and hangs his head.

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"Boomer. We will show you what a great life is like. Just trust us," Zimmer captioned the video she posted on her TikTok account streetlifetothesweetlife.

The clip has since been viewed almost 40 million times, and users in the comments section are heartbroken. What could have possibly happened to this poor dog to make him so terrified?

In an interview with The Dodo, his foster mom revealed that she received a message in February from someone who had been feeding a pack of strays every day.

When Zimmer discovered that a big snowstorm was on its way to Texas, she made the decision to try to save as many of them as she could.

"We got three dogs from that pack that day [and] Boomer was one of them."

The young stray had clearly had a difficult life.

At the vet, he tested positive for heartworms. He also had an untreated break in one of his legs, and it appeared he had been shot with a pellet gun at some point.

Zimmer's heart broke into a million pieces. Especially as she took him home and quickly realized that he was afraid of going inside.

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"It was clear that he had never been let inside the house and he wanted to come in," she said.

The young foster mom has spent the past month earning the pit bull mix's trust and reassuring him that he is wanted in her home.

The little stray still has a long, rocky road ahead of him, but he is taking his new life one step at a time.