monsters with attack mods?

i was (and still am)doing the thunderhead keep mission.i was fighting a frost giant and he was hiting me with life stealing 3.vampiric mod?i think it is.i wouldve tooken a screenshot but i dont know how.but anyway has any1 else fought an enemy that had a noticable mod?

the enchanted swords seem to have vampiric from my experience

They also put bleed on, don't they? I can't say for sure but it sounds like they use mods. I'll put this in Questions & Answers so it will get the answers it deserves.

If you're getting hit by life-stealing, that means the weapon he's wielding is vampiric. If it dropped, someone in your party got a 3/1 vamp weapon