Mikey Musumeci is a five-time IBJJF World Champion and the first American to win back-to-back black belt world titles. A berimbolo specialist who pioneered IBJJF-legal footlock attacks at lighter weight classes, he became the inaugural ONE Flyweight Submission Grappling World Champion in 2022 and defended the title three times before signing a landmark pure grappling deal with the UFC in November 2024 -- the first of its kind in UFC history.