Don't know if it was just a miscommunication between whoever named the item and the designers behind it, or if someone just doesn't actually know what the word "stun" means, but the Arc Grenade doesn't stun in multiplayer. After throwing one onto a player entering a doorway, he immediately shot me to death.
Kill cam showed his screen becoming pixellated much like what happens to Titans hit by them. Unfortunately, pixellated and stunned are not the same, and trying to pass off a hazy screen as a stun is insulting and lazy. Whenever y'all can get around to changing the text on Arc Grenades or making them actually stun, I'll be looking forward to it.