Just kill him and you should be fine

Get 1 reaper 1 rock drake and 18 megalosauras and victory

Have a friend for the genesis 2 Rockwell but for aberration Rockwell 15-18x megalosaurus 1 reaper and 1 rock drake and tons of shotgun ammunition and the strongest shotgun you can get.

Drinking a cactus broth will make Dino’s not Agro to you

Me and my 2 friends had 250 shot guns and 500 ammo each and did it with fine

Use a megalosaurus army and ride around on rock drakes shooting the tentacles with a shot gun

Have the strongest pump action shotgun you have and use cactus soup to make yourself invisible to Rockwell, doing so he will never attack you while you are under the effects of the soup

Just Slurp down some Cactus Broths and get some 200+ pump guns and run in a circle and shoot the tentacles (Would recommend starting on one of the ones closest to the bridge to Rockwell’s heart and move around it from there) then shoot the heart since that’s how you actually kill him

1-10 ppl and a few rock drakes at least 200 mele hope this helps