Went ahead and farmed 57 feast stacks since PBE made it so you can stack Second Wind and Overgrowth

https://i.imgur.com/hWlrn50.jpg

if you can believe it, he's still killable by the enemy team through grasp and second wind's regen, despite hand-picking the enemy champions to not have % health damage.

of course, it took quite a long time for them to get me that low, and since my E could do 31.5% of their health i just took them out before they could defeat me. surely a couple dozen more feast stacks and my healing would have outpaced their damage.

i made sure my masteries were visible in the screenshot so you could take a look at the values this late in a farm-oriented custom game, though i admit i could have taken this a lot farther.

If I initiated a new "Sion Project" (if you don't remember the Sion Project, go ahead and google it. it's probably the first result.), Cho'gath would have to be the new candidate. He's hilariously more efficient at gathering HP than Sion is even with the aid of all 3 minion waves, sadly. though we would likely have a similar setup so that Cho'gath could get the most out of overgrowth.

As a stretch goal, some of you may know that continues to heal through fountain turret damage. Fountain Turret does 2000 Pure Damage per second. so we just need to get 5% of Cho's HP to exceed 2000.

AKA, 40001 HP and I project Cho'gath can tank the Fountain indefinitely.