You see The Plasmother
"Blubb"; "Blubb Blubb"; "Blubberdiblubb".
Abilities
Melee (0-100+?), Poison Ball [May paralyzes you OR poisons you up to 37 Hitpoints per turn OR damages you (0-108+?)], Poison Berserk, Sudden Death (300-800+), Summons 0-2 Defilers.
Damage Taken From Elements
Physical 
Death 
Holy 
Ice 
Fire
Energy
Earth
Location
Pits of Inferno - Verminor's Throneroom.
Strategy
Try to block it with a Knight and use Sudden Death or Death Strike. Wild Growth and Magic Wall will help your team a lot.
Loot
0-173+ gp, 0-13 Platinum Coins, Demonic Essence, 0-3 Black Pearls, 0-3 Small Sapphires, Soul Orb, The Plasmother's Remains (always).