Losing a pet is like losing a family member. Millie Bobby Brown is in mourning after her big, beautiful dog Dolly has died. She was always by the 16-year-old’s side from the time the Stranger Things star was just seven-years-old. Millie took the Bullmastiff on locations shoots all over the world, and is remembering her “best friend.” She posted a video of her most cherished moments with Dolly to her Instagram account on Aug. 3, set to Bruno Mars‘ “I Know You’re Somewhere Out There.”