Logan Echolls

Who?

She, in season three of Veronica Mars when Logan and Veronica break up-

Oh my God, it is her

... and there's a little girl that Logan befriends that's like the little sister of somebody Dick's hooking up with.

And she never returns.

But ch- they, like, form this, it's like a bottle episode where they form a fast friendship.

And-

It's Dick's girlfriend's little sister that he leaves for Logan something.

I think that's pretty integral.

Based on your description, this kind of is giving me a little bit of Logan Eccles from Veronica Mars.

He was wearing puka

shell necklaces like it was his job.