Hearthpwn

So much flavor!

I always thought that bouncing was a mechanic that didn't have enough cards, these look really cool.

Also everything seems really balanced, usually custom cards are crazy powerful. They could just put this in the game right now and probably not have any problems.

You basically have a probability of 1/3 (or 1/4 if you have played 2 chain gangs) off the first battlecry trigger getting it, by the grumble battlecry triggering first. And it has a probability of 2/3 (or 1/2 if you've played 2 chain gangs) off the second battlecry trigger of it happening. It also has a decent chance of spawning a second taunt divine shield body on the second battlecry trigger. Even if you don't get the trigger though the combo seems really strong, and just the 2/4 taunt body seems good in the midgame.
We'll see in a few days once the patch rolls out how good this deck is, but I think your list is one of the most optimized that I've seen, and this deck has a real possibility of being the best deck in the game.
I'll definitely be playing a ton of this combo deck. 

I would actually recommend Lone Champion over Feral Spirit, not only is the deck pretty threat light meaning that it is very likely that you will be able to activate the battlecry, there is not a small chance that Shudderwock can get the divine shield and taunt if it triggers before the Saronite Chain Gang battlecry or after the Grumble, Worldshaker one. This would mean that along with the healing from Lifedrinker battlecries that you might end up with the Tirion Fordring body protecting you from a lethal backswing after the first Shudderwock.

I think most people are missing the point of this card. I see it merely as a way to force draw Fire Fly so you have guaranteed mana filling and combo activators in a rogue deck. Rogue also has multiple ways to make up for having a bad tempo play on turn 4, especially with activated combo cards.

The only combo deck I could see it in would be "spell" hunter, where you can guarantee Kathrena Winterwisp on turn 8 that will pull King Krush and Giant Mastodon.

While this deck wasn't designed for the ranked environment, Big Priest has been a viable ladder deck since Knights of the Frozen Throne, even going so far as to be ranked the #2 deck in the game on the TempoStorm Meta Snapshot on December 18th 2017. With the rotation of many of the staple aggressive cards, and the ability to ban Warlock in the tournament environment allowing us to cut Silence from the deck, I expect Big Priest to be an extremely powerful deck, especially in tournament.

I didn't come up with this style of deck, I simply tuned it for the tournament meta that I'm expecting in Tespa.

Seems ok, kinda sad it's a deathrattle, so silence is even more valuable against it than it would normally be.