What is this "Resisted"?

Be Mine Beginner
Apr 21, 2009
Don't get me wrong, I know what resistance is, defense against magical damage. What I mean is whenever I use Powder Monkey's Palisade and detonate the resulting barrel, pretty much 100% of the time the enemies "resist" damage. The thing is, I can't exactly tell if the barrels are doing any damage at all because I usually use an AOE skill to detonate it in the same round. I can't tell if the damage done is from the AOE or the barrel. Even if it is from the barrel, what is this "resisted" then? Does it mean they are actually resisting some of the damage the barrel is supposed to do? Is it like a block to magical/enviro damage? What variables affect this reflex, and why does it happen practically every single time I use Powder Monkey's Palisade? Thanks!