Gorged Shadehound

EDIT: see info below.

I killed the elite mob today on 02.12.2020 inside the maw.

Yes, it was simply an elite and not a silver dragon rare.

Gorged Shadehound
Health: 559k Elite
Area: Prodigum
/way 53,5 79,5

It was part of an event where you first have to kill 6 packs of mobs. Each pack had two Shadehounds and one elite caster mob.

First the boss was not attackable but after the 6 packs death he ran into a cave and was attackable. At 52% HP he jumped one floor deeper into the cave and you could follow him down with a chain.

Inside the cave there are stones on the floor [item=183787] that you can pick up and use. They summon a crystal that gives a +20% dmg taken debuff to the dog and -20% for the players around him.

Best of all, the mob does not regenerate its HP when you die! So I could kill him alone as a hunter, even with the red eye of the Jailer.

The dog is part of this achievement: Hunting Party

I guess the events rotate daily and the mob is probably not always there.

AND it did not drop the mount [item=184167]...

It dropped:
1 x [item=176862]
5 x Aethereal Meat

EDIT:
I have now killed the mob 3 times with the same char.
How do you ask? Well, I went into the maw again yesterday (02.12.20) to see what is in the area above the Beastwarrens zone, more about that later.

But then I saw that the hunt event was available for me again. So I killed the boss again.

This time there was only grey vendor trash as loot.

This morning after the EU reset the event was again available for me, probably because of the hotfix from Blizzard.
So I killed the boss for the third time and this time the loot was white cooking ingredients and grey vendor trash.

The zone above the Beastwarrens zone is called "Desmotaeron" and the only thing I found there was DEATH.

When I entered the zone I was not very attentive when I noticed it I was already dead.
There is a debuff called, I only have the german name and I couldn't find it at wowhead, "Grabeskälte".

The toooltip says every 2sec you get 5603 frost damage, but in reality it was only 5400dmg.

I have seen one elite mob that looked like the typical maw caster mob but it was lvl61 and had 1278k HP...

Hotfixes on Dec 15 they changed it to only drop eligible loot once per week.

"The rewards from Gorged Shadehound can now be looted once a week."

https://us.forums.blizzard.com/en/wow/t/hotfixes-updated-december-15/734092/39

The quest item [item=183057] for the achievement Deciphering Death's Intentions drops from this guy.