Bedbugs
Bedbugs are terrifying, feeding on sleeping humans in the privacy of our own beds. These little bloodsuckers have been the bane of thousands with their resurgence in the U.S., and their violent mating habits certainly aren't going to win them any more fans. A male bedbug stabs the female in the abdomen with his sharpened genitalia and inseminates her directly in her body cavity. The male bedbug — not exactly known for his brains — will often attempt to mate with another male, punching a hole in his abdomen in a case of mistaken identity. While female bedbugs have evolved to grow a mass of cells associated with defense against it, male bedbugs don't have that protection and often die after being speared by a male's needlelike member. There is one upside to bedbug sex, however: bedbug seminal fluid is antimicrobial, reducing the pathogens introduced during the dirty deed.