You're talking about Alatreon I'm assuming, and here I am feeling the same about Barioth
Sent up an SOS flare and actually got a full squad response over the weekend. Bodied Nargacuga, Glavenus, and Tigrex shortly after so I'm back making my way through campaign.
Yeah me and my boy finally got him on the second attempt last night. You have to have his move set memorized and be as relentless as he is when doing damage. I think the difference maker this time was using the flinch shot to knock him out of the air. We were able to survive 3 or 4 specials. Got absolutely no indication on how close we were to killing it. I think all other non siege monsters, bar Behemoth, drop slinger pods at 30%, 20%, and 10% health. After that 3rd special we were just praying it would go down. It got really touch and go for me - we'd died at the 2nd special and Alatreon wanted to fukk with us individually after that. He had me up against a wall and started spamming AoE attacks, followed up with some were he was chasing me down. He has one where he starts an AoE, then will fly right above you and let it off
. No clue how I survived that one. He had me dead to rights at one point, stunned with like a quarter inch of health, struggling to switch to my Max Potions for when I recovered, but he switched his attention. My friend ran Dragon Dual Blades, I ran Kjaar Stream Bow (Ice).
Your next roadblock might be Blackveil Vaal Hazak. Spores on the ground can't be neutralized as far as I know, so just be aware.