Working ghost

Two men were walking home after a party and decided to take a shortcut through the cemetery just for laughs. Right in the middle of the cemetery they were startled by a tap-tap-tapping noise coming from the misty shadows. Trembling with fear, they found an old man with a hammer and chisel, chipping away at one of the headstones.
"Holy cow, Mister," one of them said after catching his breath, "You scared us half to death — we thought you were a ghost! What are you doing working here so late at night?"
"Those fools!" the old man grumbled. "They misspelled my name!"