Though not explicitly named until much later, Shanks uses a form of "Haki" (spiritual energy) to glare at and scare off the Sea King.
Fans often distinguish between the two main English versions of this episode: One Piece (Dub) Episode 4
This episode explains his recklessness and unwavering loyalty. He learned from Shanks that being a pirate isn't just about fighting; it’s about knowing when a fight is worth it and protecting one's friends. Though not explicitly named until much later, Shanks
Stays true to the original script, maintaining the emotional weight and the "Anchor" nickname given to Luffy. One Piece (Dub) Episode 4