Loki died unexpectedly Tuesday night, according to his owner, Sara Kjelsvig. The feline had gone in for a routine dental cleaning at his vet earlier in the day and, while in recovery, staff noticed an increase in his breathing. Loki didn't make through the night and the vet suspects he had a preexisting heart condition they didn't know about which led to his death.

Loki, not to be be confused with the furrier "Grumpy Cat," was a male sphynx cat. The breed is hairless so wrinkles in their skin are super visible, which helped attribute to his famous title. He went viral after a photo of him wearing a rainbow fur coat surfaced.