Difficult

They try to beat me, they try in vain. And when I win, I end the pain.

related riddles

What has a spot and is very bright, is sometimes, red, white, blue, yellow or green and is often blinding.

It holds no blessings in disguise. Its rhymes are aimed at your demise, it's cast only to ruin, Whatever you are doin'.

What is the thing which, once poured out, cannot be gathered again?