Dropping in to say that the Chitterspine Ambusher with the red and white skin IS tameable, just grabbed it to verify. I remember taming it earlier, but the trauma of the OBSCENELY hard spider crab cave had me questioning my memory. Checked every color, and other than the Caverndark Terror that is mistakenly untameable, all crabs in the cave are definitely tameable. Not sure what sort of issues were run into when getting the error on it. I literally went and tamed EVERY crab, one by one in that cave, to check for untameables, and sadly only had the red glowing one untameable.
Seriously, nerf that god awful cave already. Even a geared character will get shredded in there.
EDIT: Also, Soundless really doesn't look the same ingame as the image on petopia or wowhead.

Also attached are what it looks like up close when tamed. Looks like the black skin, just far less red.
Got some choice angry words too when someone noticed I tamed it. They weren't happy with me.

Resident exploiter/bug finder that is currently looking for a bug that can safely be shared to tame unintended pets.
Found a bug? Contact me so I can investigate; it's likely far worse a bug than what you think.
For proof that I'm not making things up, feel free to look at my Blusky account; @campaigner.bsky.social