Kansas City, Missouri - This heart-melting video struck a nerve with millions of TikTok users.

On Saturday, Katie Grissum, who works in Kansas City at the non-profit animal shelter KC Pet Project, uploaded a clip on her TikTok account, katie.and.the.snoots.

It shows a Chihuahua named Amigo, who just arrived at the shelter. He's shaking like crazy and is clearly terrified of human contact, twitching and cowering in a corner. 

Katie explains in a voice-over what happened that day in the "small dog room". 

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Normally, she doesn't stay around anxious dogs, preferring to give them space, but she saw something in Amigo that convinced her she should stick around.

Katie's instincts were in fact dead-on. As she sits quietly next to the tiny tyke and lets him make the next move in his own time, Amigo slowly stops trembling and becomes more comfortable in her presence. 

Soon, he's carefully moving towards Katie and climbing onto her lap, snuggling up in her arms.

Katie admits she can hardly contain her excitement, although she maintains a calm demeanor so that she doesn't scare the traumatized Chihuahua. Her shy four-legged friend lets her pet him in the end, as he starts to doze off, feeling safe for the first time. 

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Katie ends the video by proudly adding, "I know I've said this a million times, but this is truly my dream job and I am excited that I get to share this experience with you".

With more than 560,000 followers on TikTok, the young woman is used to her content getting a lot of views, but the amount that this clip – over 18 million – got might have surprised even her.

Little Amigo's story clearly struck a nerve with the internet!