Naxx (4):
Dance boss -> fail to dance (maybe u can survive this with def cd's)
Thaddius -> stacks
Sap -> ice breath (one during airphase)
KT -> Mindcontrolled (apparently they kill other mindcontrolled too!
Ulduar (9):
Algalon -> Red circles
Iron Council -> Green shit on floor
Thorim -> chain lightning
Mimiron -> Shock, Laser barriage, red circles, frost bomb
General -> Shadow missile (with enough debuff stacks)
YS -> Big tentacle
ToC (3):
Ice Howl boss -> charging into you
Jarax -> chain lightning
Twins -> not changing debuff correctly
ICC (5):
Sindy -> Blistering cold, frost bombs
PP -> red ooze, plague
LK -> necrotic plague
RS (3):
Balt miniboss -> stand in front of him while doing bladestorm
Halion -> Meteor strike, cutter
So I think I picked up what most raids CAN kill you -INSTANTLY- from if you do not move correctly etc, with that being said Ulduar has indeed the most, so it is no surprise to me of why people come to Ulduar, think it's "oh it's a 3.1.1 patch raid, this will be easy" and then fail. I didn't count in all things that can "sub-instantly" kill you like stand in fire, because most bosses have some of those mechanics. I probably did miss to mention some though. But like MC at Lady Deathwhisper vs MC at KT are also like two obvious differences as at KT they even get a +200% dmg buff (not sure on numbers here
