Croaking Raven Doth Bellow for Revenge

That the line mocks the speech in a play called The True Tragedy of Richard III, a precursor to Shakespeare's Richard III written in 1591-2 and possibly revived by a troupe called the Admiral's Men around the time of Hamlet's debut. It has the word 'revenge' 15 times in 16 lines. So it may not only mock the players' taste in theater but also Hamlet's.

KING: The hell of life that hangs upon the crown,
The daily cares, the nightly dreams,
The wretched crews, the treason of the foe,
And horror of my bloody practice past,
Strikes such a terror to my wounded conscience,
That sleep I, wake I, or whatsoe'er I do,
Methinks their ghosts comes gaping for revenge,
Whom I have slain in reaching for a crown.
Clarence complains, and crieth for revenge.
My nephew's bloods, "Revenge, revenge," doth cry.
The headless peers come pressing for revenge.
And every one cries, let the tyrant die.
The sun by day shines hotly for revenge.
The moon by night eclipseth for revenge.
The stars are turned to comets for revenge.
The planets change their courses for revenge.
The birds sing not, but sorrow for revenge.
The silly lambs sits bleating for revenge.
The screeking raven sits croaking for revenge.
Whole herds of beasts come bellowing for revenge.
And all, yea all the world, I think,
Cries for revenge, and nothing but revenge.