I find these creatures in the quest of “The concil” (or what concil i forget)
i like these effect!
how can i get these?
many thx!
That’s the buff that’s passed between Dreven Cole and his buddies. For some reason if enemies spawn in the area after the Dreven Cole and his buddies fight, those enemies will have that buff.
And no, there’s no player skill that has that.
how do you know this?
what if some equipment-skill can give me these pretty cool effect 
Hargate’s Crystal. That is what you are looking for. It gives a purely cosmetic floating aether crystal.
The purple one is Kasparov’s crystal.
How to get them :
https://grimdawn.gamepedia.com/Kasparov's_Gamble
https://grimdawn.gamepedia.com/Hargate's_Mysteries
The exact effect from the council bosses is not available for the player.
wow! thx!! that’s what i need! 
Yes, they are neat. Too bad we only have 3 “pets” like these in the game.
Btw: You can put them in the shared stash and summon them from there, no need to actually carry them around in your characters inventory.
Neat for hardcore players especially. 