Indeed it was a time of nostalgia that hearkens back to the simpler days of one piece, where Luffy was just assembling his pirate crew.
In return for helping him protect his Treasure, Shu shu helped the strawhats escape from the angry townspeople. In a way, I think this foreshadows how everyone else wants to help Luffy.
Just as he understands their heart, both animals and objects alike take on strange human-like properties in response to Luffy’s kindness and dare I say it, innocence?
This won’t be the last time however. Later on, Going Merry would also take a humanoid form in response to the crew’s actions as they treat even their ship as a nakama.
Rewatching moments like this kind of makes you a bit nostalgic doesn’t it? 🙂