Dreaming of killing a snake implies that the dreamer can conquer the enemy or defeat his competitors.
Dreaming of cutting off the head of the snake shows that the dreamer has not encountered any difficulties, even if he encounters difficulties, he can solve them all and find a way to overcome them.
Dreaming of catching a snake, because the snake is a symbol of sex, the dreamer will naturally be mixed with some angry emotions, which also implies that the dreamer is in an unsatisfied state for the current sexual life.