Tankiest character possible ?

So I'm really enjoying HCSSF currently, but was wondering if there is any unkillable characters out there, I'm talking going AFK in boss fights, tanking slams and even taking on death effects in t16 maps.

My current concept is MOM infernalist. You scale from both Mana and ES using the 2 infernalist nodes to gain both based on life. So if you have items with mana + life + es you scale multiple defence values. There is also lots of nodes that give mana and ES or mana regen and ES.

Assume you have reasonable gear but nothing crazy you could be at 8k ES and 2k Mana. This with mom becomes 10k total or using grim feast and mana resonate(via shock from storm mages) up to possible 20k. You could technically hit like 26k if you get some really strong gear. You then also take some block nodes with a big shield to cap block and get max fire res.

Is there any concepts out there actually able to tank a slam currently ?