Which Shakespearean play includes a ghost that claims he was murdered by poison being poured into his ear?

In William Shakespeare's Hamlet (Act I, Scene v), ... a ghost speaks to Hamlet, claiming to be his father's spirit. He has come to get Hamlet to revenge his death, a “foul and most unnatural murder” (I.v.25). This ghost tells Hamlet that ... as he slept in his garden, a villain came and poured poison into his ear. The villain was his brother.

In this play, Shakespeare's choice of murder techniques is called one of the most important deviations of the play. Historians also say that this plot idea was probably derived from the 12th-century ''Historia Danica,'' by Saxo Grammaticus. In Grammaticus's story, a king is killed (by stabbing) by his brother in front of witnesses. And all known reports from the 11th and 12th centuries state that no written references were ever made in folklore about any murder by poisoning through the ear.

Additionally, a French surgeon, Ambrosie Parex, who was Shakespeare's contemporary, was suspected of killing the French King, Francis II. He gave the king an ear infection during the course of treatment. Shakespeare, it has been said, may have based his murder idea in Hamlet upon the incident with King Francis II.

Over and above the murder technique used to kill Hamlet's father, Hamlet felt and feared that the ghost who told of the murder was not his father's ghost. As Hamlet said at the close of Act II, it is the devil who ''abuses me to damn me.'' This is the key or decisive factor (idea) for Hamlet.