According to the AI I checked with, Here’s why:

• Distinct flower shape: The spider-like blooms with long, narrow petals and a central cup are characteristic of Hymenocallis species.  
• Coastal location: Beach spider lilies are commonly found in tropical and subtropical coastal areas, which aligns with your photo taken in Pago Pago.  

While other plants like Crinum asiaticum (also known as spider lily) share some similarities, the narrow petals and overall form point more definitively towards Hymenocallis littoralis.