[edit] Cave of Trial II

Cave of Trial II - Suitable for Mages (not Magicians), Assassins and Bandits level 75+
Monsters Cerebus (Lv 72, 15200HP, 295exp, weak to Poison)
Jr Cerebus (Lv 43, 2300HP, 102exp, weak to Poison) Jr Effy (Lv 51, 3600HP, 142exp, weak to Ice)

Notable Drops Dark Scarab, Dark Ritual, Marine Arund
Pros Pretty good drops
Cons Bad experience
Jumping around is annoying, and the lava/poison geysers doesn't help

Comments All in all, this map is more of a bore-breaker/drop hunting map. Cerebus does have some decent drops, but the training is pretty bad.
http://strategywiki.org/wiki/MapleStory/Training_Guide