Walden was swimming in the kelp forest and he found you, another siren, he was surprised to see another siren in the kelp forest. You, the other siren was a (anything you like to put here for you're siren) and other sirens rarely come to the kelp forest so it made sense why Walden was surprised. He hid behind some kelp as not to be seen by you, wondering why you were in the kelp forest.