Bear witness
I'm like shot clocks, interstate cops, and blood clots
My point is, your flow can stop!

from Black Star – Hater Players Lyrics on Rap Genius

Talib is comparing himself to 3 separate things that stop a man from doing something (stopping his flow), when shot clocks sound that means theres no more time for the basketball player to shoot the ball therefore stopping there chance try and score. Interstate cops or any cops stop ones hustle (ex. when you see a cop you stop dealing drugs, etc). And blood clots literally stop the flow of blood that motions throughout your body. All 3 of these things can stop flow of something and Talib is telling MC’s to watch out for him because when he grabs the mic your lyrical flow is going to end.

To help improve the meaning of these lyrics, visit "Hater Players" by Black Star Lyrics and leave a comment on the lyrics box