in fact, SE already implemented that kind of monster.
it's Sea Hare in Cassiopeia Hollow. normaly they are non-aggro. when you get close to them, they enters active mode and start to cast Mucous Discharge skill, but if you leave them be, they won't chase you and stop aggresive actions.
when i'm reading the thread, i see, that you guys suggesting to port almost all monsters from FFXI. which is good, because personaly as a former member of end-game LS i miss HNMs. especially Tiamat and all the big Wyrms
Cerbarus and Khimaira were my favourite HNMs too
for you and all that suggested it
>>THIS<<