Yup, found this out yesterday but the website was down so I couldn't update my post.

Bloodseeker and Sandclaw Sunshell are both rare spawns.

https://www.wowhead.com/npc=154714/bloo ... id=3126607

I found 1 at Ashen Strand 31.02, 44.98.

My theory is that they spawn in the location of a Deeptide Fingerling. Which you can't kill unless you pet battle with it.