Dododex Says you can't knock it out with fists cause 100% chance of death but they are wrong. I just did it on official ASA with a level 90. The trick is you have to let the argy periodically eat your body to regen health. I had to die like 10+ times but it is doable. Some of those deaths were not intentional tho.

Anyway the method is simple (ASA)

Build

-one stone foundation

-three stone walls

-one slanted stone roof

Drop foundation. Put 2 walls down next 2 eachother as double wide doorways. And the 3rd as a secret door. Attach the roof to the middle wall extending out toward the unused opening acting as a funnel. Find low argy. Lure into opening. Go out thru secret door as it follows you in. Viola. Trapped argy. Now position yourself behind the secret door so that your punches hit but his attacks don't and Bam. You k.o. an argy beach Bob style day 1 with limited supplies. You may however want a few beds tho because as I stated. You will be dying a lot and feeding it your own body to keep its health up.

There is however one caveat. Flyers do not like staying in traps with no players in render distance. So you do need somebody to stay nearby to ensure he doesn't fly away when you die.