Mirko "Cro Cop" Filipovic became the first UFC fighter to be sanctioned under the UFC's drug testing program administered by USADA. He was provisionally suspended after withdrawing from a fight due to a potential anti-doping violation, later admitting to using HGH to treat a shoulder injury. Considered one of the greatest MMA and kickboxing heavyweights, Filipovic won championships in both sports and was known for his powerful left head kick.