User blog comment:Kaido King of the Beasts/Chapter 884: Sing or Swim/@comment-31429799-20171103140934/@comment-30127592-20171107204410

It just seems odd to me that he'd be able to change the shape of his body using observation haki, which has always been more of an observational/mental power, in opposition to the physical armament and "spiritual" (can't come up with a better word for it) conqueror's haki. That's the reason why i think his body is permanently composed out of mochi similar to luffy's rubber body, and he's somehow using the properties of mochi to evade attacks he foresees with his haki, similar to how luffy "uses" his immunity to electricity and resistance to blunt attacks.

it's not that him changing shape with observation haki as a reflexive evasion wouldn't fit with the concept, but that it seems rather improbable to me since there are more feasible possibilities.