When Jessica Shyba brought Theo home for the first time, she had no idea what to expect.

She received a "vague description" of the seven-week-old pup's breed — part boxer, part shepherd, part lab — but that was about it.

She had no idea Theo would quickly become a "beloved puppy brother" to her kids.

And she certainly didn't expect the incredible bond the dog would go on to form with her youngest: Baby boy Beau.

"On his third day with us, Theo fell asleep on Beau and I as I rocked him down for his afternoon nap," Shyba writes on her mommy blog. "I was practically howling at the cuteness-and nearly woke them both up."

The next day at nap time, Theo surprised Shyba by appearing outside Beau's room as if asking to be a permanent part of the "ritual."

"[A]nd so began what I can only describe as the most organic and beautiful friendship I have ever witnessed," Shyba says. "Each day, Theo meets us at naptime and waits patiently for Beau to fall asleep. By that time, he’s also sleepy, so when I hoist him onto our bed, he stumbles over to Beau and plops right down on top of him. And there they sleep, entwined, for at least two hours."

To celebrate their interspecies relationship, Shyba launched the Instagram tag #TheoandBeau, and has been posting photos of their daily dognaps ever since.

[H/T: 22words, photos via Jessica Shyba]