Three or four, I can stab through or rule the seas. You know my cousins. What am I?

Why this works

This riddle plays on the word "fork," which has multiple meanings. The phrase "three or four" refers to the prongs of a fork, which can have three or four tines. Additionally, the mention of "stabbing through" alludes to the fork's use in eating or cooking. The reference to "rule the seas" cleverly connects to Poseidon, the god of the sea, who wields a trident, often depicted as a three-pronged fork. The final line about knowing "my cousins" hints at other types of forks, like garden forks or pitchforks, reinforcing the idea of the fork's various forms and functions.