Yellow Against Black

A poetic riddle about a... Well, take a guess! The answer is in the poem.

Yellow against black by the path in the park.
Yellow against black at your feet in near dark.

Red against yellow is the dangerous fellow,
But that doesn't make the meeting more mellow.

He shall bruise your heel. You shall bruise his head.
Yet all I can feel is a deep sense of dread

That the future for its kind is so bleak and so stark.
Yellow against black by the path in the park.