Thescaryfact ™ on Instagram: "Some species of flatworms reproduce through a behavior known as p@nis fencing. Each flatworm has two bifurcated p@nis structures and attempts to st@b the other during mating. The worm that successfully penetrates its opponent remains male, while the loser is forced into the female role and becomes impregnated. This violent reproductive strategy evolved because producing eggs requires far more energy than producing sperm — so neither worm wants to lose. It’s one of t