Metro 2033: Broken Gasmask Syndrome.
I was up on the surface, micbreathing into my fogged-up mask, when I was ambushed by some mutant rats. I did manage to shoot them, but they cracked up the visir to my gasmask, a long, long haul away from a replacement one.
It was... Rather awful, staggering around aimlessly in desperation in the snow with my vision washing out and my lungs slowly shriveling up in my chest. When I did finally bite it, it felt like a liberation...
I was ambushed by an albino radscorpion in Fallout 3 once, too. I didn't even hear it, being inside a pitch-black metro tunnel. Suddenly, I turn around and I've got those beedy, black eyes staring at me. "Yo! I like violence too, check it out!" it seemed to say before I got a stinger in my face. :<