The smell of dead crickets and lizards. You may be thinking, huh, Renoux? What? What a random pet peeve. Allow me to explain. My brothers have a gecko, which is a type of lizard. Lizards eat live crickets. When the crickets die before being eaten, they are left on the bottom of the cage to decompose, because the gecko won't eat them dead. Also, lizards tend to poop very often, also releasing a rather unpleasant odor of dubious origin. So, whenever I walk into my brother's room, (not something I do normally, for good reason, but is necessary on certain occasions), it smells like decomposing crickets and lizard poop. Eew. Just eew.