Well, that's odd. I was going to say Crocs socks are just regular socks with different colored spots near where the holes are. That's the kind I've seen for sale at the Crocs stand in the malls around here.
But when I went to get a pic to post, they're different.

Here are pics of
Crocs socks currently sold on their website. You might want to ask your dh if the ones he's seen are a solid color, or have the spots.
No holes, though.