Blue glowing mob/ spoil system

I have OFS on dualclass at 85 lvl
I attack mob, when he die then glowing on blue how to get items from this mob what skill name?
I dont have anymore spoil/swepper skills. Why this mob glowing?
How spoil system work after awakening? (on dualclass)
Is spoil system on dual class work same like on mainclass?
What is diferences betwen wild plunder and rewerse plunder
Thete is only two skills for spoils or one for changing chances for spoil?

I know Kung Fu teach me Spoil now

 

Target a mob, use your plunder skill/stab.
You can then get (or not) an item instantly depending on the old good RNG.
Tadah, that is how spoil works.
Both skills should work the same, spoil works the same way in main or dual class. Gl with it

 

but why sometimes mob is blue, i cant pick item from him then

 

Mob is blue after die becuse it was spoiled succesfully. Mobs with no spoil drop are nor glowing blue after death.