One of the greatest careers in MMA history came to an end on Friday when Demetrious Johnson announced his retirement from the sport.

Former longtime UFC flyweight champion and ONE Championship titleholder Johnson (25-4-1) entered the cage as a special guest at ONE Championship 168 at Ball Arena in Denver and told the crowd that he was done with MMA fighting.

It was an emotional speech from “Mighty Mouse,” who moments later became the first fighter inducted into the ONE Championship Hall of Fame. Johnson did not rule out a future return to grappling competitions, but said that he no longer has a future in the combat sport in which he became so famous.

Reactions to Johnson's announcement poured in on social media, and you can see the overwhelming praise for his legendary run below.

Mike Bohn

Terrance McKinney

Ariel Helwani

Alan Jouban

ONE championship

Derek Brunson

ONE championship

Demetrius Johnson