User blog comment:Kaido King of the Beasts/Chapter 884: Sing or Swim/@comment-31429799-20171103140934/@comment-12.106.174.131-20171103165516

Katakuri does not become Mochi, he only is covering it upon himself like Trebol was doing. Trebol played the same thing, moving out of the way the opponent attacked to appear like he was logia, but in the end he was simply faking his body. With Katakuri's haki he is just that much better at moving his body out of the way so it hits his faked Mochi parts. Trebol too was cut in half but was unaffected since he moved his body out of the way.