What is the most drastic change in style of a fighter you've seen?

[greynotsoold]

Barrera actually changed direction twice, as he began his career as a boxer, becoming more of an all-out type fighter when he began appearing on PPvs, before becoming a more thoughtful fighter later on.
Cornelius Boza-Edwards began his career as more of a boxer until Bazooka Limon threatened to kill him. Boza-Edwards decided not to go without a fight and became legendary for the wars he subsequently engaged in.