Roger -- AKA Kangaroo Jacked -- lit the internet on fire back in 2015 after pics of him crushing a metal bucket with his hands went viral.

The 6'7", 200-lb. 'roo was living at the Kangaroo Sanctuary in Australia ... and his videos and pictures showing off his Schwarzenegger-esque physique were a big hit on the web.

"Sadly Roger has passed away of old age," owner Chris Barnes announced on Facebook. "He lived a lovely long life and was loved by millions around the world."

Barnes rescued and raised Roger as a joey after his mother was killed in a car accident ... and in 2016 announced the kangaroo was dealing with arthritis and vision loss.

"We will always love you and miss you Roger"