Killer sperm kill any sperm from other males found inside the female.
Blocker sperm join flagellas (the tails they use to swim) and block any approaching sperm from other men.
Egg-getters go for the gold in that great race we call sex.
And family-planning sperm (cute name) kill any and all sperm it can find.

The sperms which kill other sperm do so with the enzyme found on their heads. This enzyme also eats away at the outer membrane of a female egg shell, which is the primary use for it. Somehow along the way, though, it became evolutionarily advantageous to use that enzyme to destroy your potential enemy by chewing through the flagella of an “enemy” sperm and cutting the opponent in two pieces, meaning that the sperm opponent will neve make it to the finish line and instead will languish and die without fulfilling his only purpose of existence.

The blockers form a wall and, well, they seem to be some of the original cawk-blockers.
(seems some blockers chose to be born, so they can block for longer than 3-5 days!!!)
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