How is Shakespeare's scene where Clarence dies both frightful and amusing in Richard III?
In Act I, scene four of Shakespeare's Richard III, Richard has outwardly arranged to pardon his brother Clarence (who he secretly took steps to have arrested and put in the Tower of London), while he has (again) secretly made other arrangements—to have Clarence murdered.
The scene is frightful—but rather than amusing, personally I find it disturbingly ironic. The irony comes from the substance of a dream Clarence (George Plantagenet, 1st Duke of Clarence, 1st Earl of Salisbury, 1st Earl of Warwick) has had that he shares with Brakenbury. Clarence describes having escaped from the Tower (in his dream) and is sailing to Burgundy. While this is a place in France, it is also the name of a kind of wine. Wine will become an important detail in the "horror" of scene four, so it is also not just a play on words, but foreshadowing as well. (Shakespeare was a clever and artful writer.) Clarence goes on to describe sailing with his brother Gloster. They look (across the English Channel, we assume) toward England. "Wars of York and Lancaster" is a reference to the War of the Roses—the battle between the two royal houses for supremacy in England—and, of course, the throne.
Clarence is filled with guilt for having switched sides more than once during the Wars of the Roses…
Gloster and Clarence (still in the dream) recall the "thousand heavy times" they had experienced during the war. Suddenly, as Gloster and Clarence walk on the "giddy" (unsafe; weak) hatches on the deck, Gloster falls into the water to his death, and Clarence has a flash of insight in the dream (foreshadowing, again) of what it would be like to drown.
Methought that Gloster stumbled; and, in falling,
Struck me, that thought to stay him, overboard
Into the tumbling billows of the main.
O Lord, methought what pain it was to drown!
What dreadful noise of waters in my ears!
What sights of ugly death within my eyes!
Even though Clarence tries to reason with the murderers that he is a king's son, and it is a sin to kill him, they will not listen. Clarence, even in death, cannot believe Richard's betrayal. When the murderers kill Clarence, they "drown" his body in a "vat of Malmsey wine."
Take that, and that: if all this will not do,
I'll drown you in the malmsey-butt within.
[Exit with the body.]
With the "drowning" of Clarence's body in the wine, the irony is complete, in that his fearful dream regarding his brother's drowning actually foreshadows his own death—murdered but then placed in a "vat" or "barrel" of wine.