Why doesn't Chopper return to reindeer form when unconscious?
Welcome to Anime&amp;Mange SE @floweringdusk,
Chopper doesn't change form because the &quot;little&quot; form he is in is the one that he is accustomed to the most.
On the other hand, losing consciousness or falling in water doesn't stop the DF powers. In sea water, DF users gradually lose their ability to move and are extremly weak thus they are called &quot;a hammer&quot; in regards to swimming.
If you remember, after the fight between Luffy and Rob Lucci (think chapter 427) when Lucci is knocked out but still regains his leopard form regardless.