On October 17, 2015, he was scheduled to fight boxer Terrel Williams. During the bout, Williams repeatedly landed "rabbit punches"—an illegal blow targeting the back of the neck or the base of the opponent's skull.

Colón protested, but the fight continued.

After the match, Colón collapsed and was rushed to the hospital, where he was diagnosed with a severe subdural hematoma. This injury caused a coma and irreversible brain damage, leaving him wheelchair-bound and requiring round-the-clock care.