Draftmite
A Draftmite is a nano-sized gremlin that resides in personal computing devices, seeking out written documents in order to insert errors and writing glitches into them when the composer is away from their device and is why what seemed to be an error-free document will all of a sudden have mistakes in it.
"The frustrated writer could have sworn his story was flawless when he submitted it, but he later found a number of errors, due to the draftmite, which had infected his computer."