anyone know the shoggoth buff?

[GucciBang]

I did not see anything

I'm using endless 76

[Desoulad]

I did not see anything

I'm using endless 76

If you equip the set he will show a blue ring below him like heroic pet with hearts coming out of it. You can test this by unequipping a piece of the set and he will lose the ring. I think it gives him double damage or something also but I didnt check if it changes on pet screen or if its a proc or something.

[Futumsh]

It doesn't change his stats and isn't displayed anywhere, just you see the lavender-ish circle and hearts, and his passive attacks and AA do double damage if it's on.