(LOS ANGELES) — The cast of Fuller House, who just wrapped the final season, are grieving the loss of one of the show’s most integral characters: Cosmo the golden retriever.  He was three years old.

The audience was introduced to Cosmo when he was just a puppy in the first season of the Full House spinoff, where the was established as a descendant of Comet — the trusty golden that watched DJ, Stephanie, and Michelle grow up in the original series.

Fuller House announced Cosmo’s unexpected passing on their official Instagram Monday, “We’re sad to share that the Fullers’ faithful dog Cosmo, who grew up on our set, passed away after complications from surgery. There will never be another quite like our boy.”  The show included a handful of adorable photos of Cosmo throughout the seasons and added, “We’ll miss him forever.”

Various cast members of the Netflix series honored the four-legged scene stealer on Monday.  Candice Cameron-Bure, who plays DJ, wrote on Instagram, “Our sweet boy Cosmo is now running around in doggie heaven. I imagine he’s playing with Comet right now.”  She included a slideshow of her favorite photos of her furry co-star and added, “Cosmo has been in Fuller House since the start and we are heartbroken that he passed away during surgery complications. You’ll be so missed love bug.”

Jodie Sweetin, who plays Stephanie, offered a sweet tribute on Instagram, writing, “Our little Cosmo was always such a good boy,” and continued, “Say hello to Comet for me, buddy.”

Possibly the most tear-jerking tribute came from Cosmo’s official Instagram, which is run by his trainer, who revealed, “In my 26+ years of being a professional animal trainer Cosmo was one that took residence in my soul and nothing will ever replace him.”

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