What are the white lights near the Coastal Cave in Elden Ring and what do they do

gamepur.com:

There are multiple mysteries for you to uncover in Elden Ring as you explore the game. You’ll find that you’ll have to go out of your way and experiment if you want to figure out how every little detail works, and not everything will be told to you immediately. For example, over by the Coastal Caves, to the west of The First Step point of grace, you’ll find white glowing lights around these pillars on the beach. What are the white lights near the Coastal Cave, and what do they do in Elden Ring?

When you stand near the white lights, you’ll hear a distinct pinging sound as they race by. As the lights grow further away and circle the pillars, the sound begins to fade before returning once more when they get close to you. If you stand in the middle of these lights, nothing happens. You can find them on the coast, to the west of the starting location.

You have to attempt to slash at the lights right at the very front.

The lights are footsteps, and they’re hiding a hidden enemy that you should be able to down with a single slash. Once the enemy has been downed, you’ll be able to receive an Ash of War called Stamp (Sweep). It’s an affinity you can add to swords, axes, and hammers while you’re at a grace site.