Running Maldruxxus dungeons to farm for undead pet book and I cant get rid of Fodder to the Flame. So randomly a demon pops up that i have to kill. Just in case the devs dont know, Hunters do not have Throw Glaive 
Edit: It goes away and is replaced by Fleshcraft after you do the quest to create the primus’s blade. Whew…
Just had this happen on a level 80 shaman, while going back to farm the Slime Serpent in Plaguefall. I was -very- surprised to see the infernal spawn on top of me (Spell ID: 328605) while not playing the class it was designed for!
Still happening, for what it’s worth. The demon can be killed, but is scaled to the player’s level, so not entirely one-shottable. Doesn’t hurt you very much, but it can be inconvenient if you’re trying to get out of combat.
This just happened to me on my DH but I was in Codex of Chromie. I’m extremely confused. Not sure if it’s a bug or some weird thing for that specific scenario ?