Any flying enemy in anything ever.
Particularly the Cazadors of Fallout New Vegas and their ability to mysteriously disappear and stay hidden until I use an antivenom (at which point they see how many stingers they can fit in my face).
Particularly the Cazadors of Fallout New Vegas and their ability to mysteriously disappear and stay hidden until I use an antivenom (at which point they see how many stingers they can fit in my face).