Arcane Casters only. This is still first come first serve. It is preferred you have played this before, but not required. Reason for Arcane Casters only is that they can bypass high AC creatures, basically an experiment. You do not have to have magic missile as your spell, as any spell that doesn't target AC and still does damage even on a save is okay. There is still roleplay involved before the fight, but I want to see how fast this creature can be taken down, My guess is 1 round, but it is also a matter of how far into the round. Everyone can still take there turn even if over killed.
Example below assumes max rolls
Round 1:
Player 1: Magic missile: 15 damage
Player 2: MM: 15 damage
Player 3: Pummeling rumble: 8 damage and pushed back vs a reflex save (the only way this doesn't take damage is if it crit saves)
Player 4: Magic missile: 15 damage
Now lets assume if failed its save and it is already dead at this point, but I still play it out as if it didn't die, and I don't tell you it is dead yet, and lets assume it now goes in init making its attacks. Lets assume it downs player 1 into dying 1 or dying 2, it is dead, so it can't but I'm getting to that.
Player 5: Grim Tendrils: 8 damage and 1 persistent bleed vs a reflex save
Player 6: Decides to medicine player 1 cause player 1 is in dying 1 cause of it.
After all 6 players go I announce combat over, and that it died after player 4 went. Player 5 makes sure it is dead and player 6 never had to battle medicine player 1 cause player 1 never went into dying 1 or dying 2, but player 6 was ready to play doctor just in case. Now let's assume it didn't die, we go to round 2. Let's also assume player 6 failed medicine check and player 1 went down from a crit. Players go and player 1 rolls a 1, or maybe just a failure on a death save. In the combat tracker I write player 1 died, or did he, depends upon the retcon? Or dying 3, or maybe someone can retcon and he not dying 3? Everyone takes there turn. At the end of round 2, I say it died after player 3 went, meaning players 4, 5 and 6 can retcon their actions to save player 1 assuming there actions weren't battle medicine/heal to save player 1.