He does corrosive damage not radiation.

He’s a Predator reference. He looks like a Predator and the mission is even called “What The Hell Are You.”

Swarm is the BEST mod in the game. It tracks the boss if in range, kills adds and rechargs fast with just one peice of the Ex-Cultist set. Corsus NEEDS to be in Adventure Mode.

running and gunning really helped me with this boss. The map is large enough that you could ignore the adds

Just keep moving and dont stop (DoT help a lot too).

I would advise to use you ping button (even in solo) so you can more easily see where he pops up when he's teleporting. Green fart gas in the way really makes it hard to see him.

Playing through the game with a friend and this is one of the hardest bosses I have fought on hard difficulty along with Ixalis and Scourge. Those adds are the most annoying ones in the whole game IMO.