Chitterspine Skitterling
Drops from Needlespine. The chitterspine make a distinctive clicking noise when they see prey in the open. Aquatic type. I believe this is the only aquatic with Black Claw and a swarm/stampede/flock type move.
The Chitterspine Skitterling is an aquatic pet found in Nazjatar that can be caught as a rare-quality wild pet or purchased from a vendor.
Guide awaiting review
Catch in Nazjatar
Search for Chitterspine Skitterling in the Zanj'ir Terrace area of Nazjatar, particularly around the Chitterspine Caverns at 42.31, 13.60 where they spawn frequently. They can appear as secondary pets during battles, so check multiple encounters if needed.
Purchase from Needlespine
Alternatively, buy a Chitterspine Skitterling from Needlespine at 39.4, 28.2 in Nazjatar if you prefer not to hunt for one.
