To be beaten to death by a large black rubber
dildo.
In the movie Lock Stock and Two smoking barrels, the character Hatchet Harry, beats a man, suspected of stealing, to
death with what happened to be at hand. Harry, also a porn shop owner, happened to grab a big black rubber cock.
This term arose due to the unwieldlyness of the lengthy phrase "He was beaten to
death with a large black rubber cock..." and was shortened to simply, "He got gonked."