Carrie Underwood is mourning the loss of her dog Ace, a rat terrier, who died Sunday night. She shared the sad news on social media along with several pictures of Ace writing, “Last night my sweet Ace left this world…he will forever live on in our hearts and be forever missed . . . He was a true friend and a good boy till the very end. I love you, sweet Ace…see you on the other side…"