Those guys should be renamed to Annoyted because they are extreme annoying.
I m level 49 right now without any legendaries so I m not maxed out.
so whats the best way to kill them? I waste so much time and ammo because they are immune to everything 2/3 of the time.
Things get really worse when there are 2 of them.
Would be nice if we can share some strategies and insight here.
The easier way?
Get maxed out , and find some decent guns for your character with the skills that you are using.
The hard way?
Push it now and try to adapt a bit , will pay off making them easier when you get the guns.
The strat is shooting them in the face.
Since you didnt link what character or build you’re trying to use I cant give you much more.
Have fun with the game 
I use Moze but my main problem is they shield themselves all the time or are immune to everything.
Isnt there a way to reduce this so they are vulnerable longer?
To my knowledge,no.Throwing grenade behind them is a good start.But moze can deal with them just fine.Their gimick is patience.Nothing more nothing less until you gear up.
She has a couple of very good/decent builds to deal with the whole game in general.
Try this forum https://forums.gearboxsoftware.com/c/Borderlands-3/Moze or making one yourself to ease your pain.
Play phasegrasp Amara? That’s the only reliable way I know of to break them out of their immune phases.
Jump and shoot.
Cryo works a little. I usually end up loading them with pellets from a torgue shotty.
They are bullet sponges, as long as you see health ticking away , keep at it.
Watch the novas, watch the purple orb that follows you and watch for him teleporting behind you and smacking you around. Oh and the flaming skulls suck too.
Flakk’em! 
They are very aggravating ( Annoying ) . Like they said phase Grasp helps, and the bear is actually good for them ( but the limited view with the bear, and sort of slow movement against the teleporting ones is disturbing ), ( I have not made a Zain yet but I would assume his decoy might be some help )
but there invulnerability is to much a lot of the time especially if there are multiple one attacking, and if you have and aggressive constantly chasing one they are just a major pain.
I do so hate bullet sponges…
- Annointed weapon with bonus to annointed
- Fire weapon (obviously) as you get a permanent +75% damage
- Atlas weapon : You just need to hit the head with your tracking shot, then you can focus on running away while still hitting 100% crit damagethanks! you tips helped me to kill them better and quicker! still annoying though
I just had to fight 3 of these at once…
Decided I had way better things to do with my time. ■■■■ that.
I found the best way was with
Moze with a regen grenade build and a mirv hex with corrosive for constant crits (it’s worked well for me) plus the flakka for added damage
Radiation weapons seems to work wonders for me. They take a while to kill, though. Such bullet sponges, not to mention the fact that they teleport around the place.