At level 32, I have had 2 battles with The Great Oowomp. When we first met, I slayed him and had over a bubble of mana left. The second time I encountered him, I had to use Spirit of Cheetah just to lose him after running out of mana with which to damage him. He dropped nothing when I first slayed him.
The problem is that I'm a Shaman at level 32, hence our class is equal but at level 34 (and he was level 34 exactly both times) he has 1 more spell circle than I do -- this gives him a better direct damage spell, DoT, et cetera. As a general rule, fighting the same class of a higher level that has met the level requirement for the spell circle above yours is a bad idea. At level 34, with my little doggie, I will beat him down repeatedly, into the late hours of the night and early hours of the morning.
-- Anbori <Obsidian Pact>