[quote=@Galaxy Raider]
<Snipped quote by Ignacious>

They have the option to remove the ability to be interacted with. Intangibility. Best to hit them when you know they’ve got it off, say on the heels of one of their attacks. Pro tip in case you scuffle with them before I get it all on paper.
[/quote]

Oh brother, I had a feeling it was something dumb like that. 
*scratches my head in annoyance*
I have a few trick up my sleeve with those kinds, but by no means I like fightin' them.