I know for a fact that PGP does that when it in the process of wiping a file. Are you sure this file just randomly showed up? The file could be the result of starting a wipe and then before it could finish, canceling or ending it unintentionally via shutting down your computer or something of that nature. Although the P2P networks use temporary file names to store data when you are downloading, I find it unlikely that they would generate a temporary file name with hundreds of a's.
I suggest simply deleting the file.

-rasem