Old Scratch or Mr. Scratch, like Old Nick, is a nickname for the devil. In the last century it was widely used in the eastern United States, especially in New England.
Scratch is attested in the Oxford English Dictionary from the 18th century onward in Great Britain as a colloquialism: “He'd have pitched me to Old Scratch” (Anthony Trollope, 1858). The source of the name is probably the Old Norse word skratte, meaning "wizard, goblin, monster, or devil", a word which was used in late O.E. for "hermaphrodite" (cf. O.H.G. scrato: "satyr, wood demon").
The character is exemplified in the short stories The Devil and Tom Walker by Washington Irving and The Devil and Daniel Webster by Stephen Vincent Benet. It is possible that the local legends containing this name were influenced by Faustian stories brought to North America by German immigrants. Old Scratch is also referred to in The Adventures of Tom Sawyer by Mark Twain.