Conversation so far:
What kind of legacy does Charles Barkley have?
During his 16-year NBA career, Charles Barkley was regarded as one of the most controversial, outspoken and dominating players in the history of basketball.
What did Charles Barkley do in his career to have a legacy?
Charles Barkley employed a physical style of play that earned him the nicknames Sir Charles and The Round Mound of Rebound.

Question: What made him controversial?
Self-contained rewrite: What made Charles Barkley controversial?