Invincible breach monster

There are some mobs named like "it that crawls" that seem to be invincible.
I start the breach last on the map and have quite the stack of HH buffs and they simply take 0 damage, are way faster than me and kill me with 2-3 hits.

wtf are those?

ah and they apparently dont get stunned or damaged when you use ailiths spells

annyoing af, dont know how many times I died to those little shits (they are hard to see as well)

Edit: and sometimes, they are invisible as well

Just stopping to say I just experienced the same thing in a breach hive. Eventually every single monster became invincible. It started with a couple of them being invisible and slowly increased as the waves progressed. kinda frustrating.