One Piece fans have been eagerly waiting for the Wano Country arc to make it to the anime for quite a while, and one of the major reasons is because fans have been wanting to see Luffy make full use of his Observation Haki mastery ever since his battle with Katakuri during the Whole Cake Island arc. While a previous episode has given fans an example of just how easily this power now comes to Luffy, the latest episode has it seeming familiar to another major comic book power.
In Episode 897 of the series, Luffy's Observation Haki acts essentially like Spider-Man's "Spidey Sense" in which he can sense dangers before they arrive. While this is like how it was used earlier, Luffy ends up using this Haki sense to prepare properly for his next fight.
When Hawkins of the Worst Generation, who has aligned himself with Kaido's Beast Pirates, arrives to where Luffy and Zoro are, there's a brief glimpse of Luffy's eyes flashing with a red light before Luffy suddenly turns and prepares to face the incoming threat. In this moment, Luffy wasn't really activating it and it set off instinctively in the face of danger.
This is how Spider-Man's "Spidey-Sense" works in his franchise. Spider-Man isn't constantly sending out some kind of energy to scanning the area around him, but instead he instinctively can sense danger before it arrives. It seems that now that Luffy has mastered Observation Haki, it just activates on its own without him needing to constantly use it.
It's kind of like how Katakuri was able to use it during the Whole Cake Island arc, but even then the series depicted him activating this power rather than it activating on its own. So maybe Luffy, in learning this power, has managed to take it one step further. But this will be put to the test as his battles in the Wano Country have only begun.
Eiichiro Oda's One Piece first began serialization in Shueisha's Weekly Shonen Jump in 1997. It has since been collected into over 80 volumes, and has been a critical and commercial success worldwide with many of the volumes breaking printing records in Japan. The manga has even set a Guinness World Record for the most copies published for the same comic book by a single author, and is the best-selling manga series worldwide with over 430 million copies sold. The series still ranked number one in manga sales in 2018, which surprised fans of major new entries.