What's this file, and how do I delete it?

Yesterday I made an Excel file on my Mac (OS 10.7.5) and saved it to the desktop. I copied the table and pasted it into an email. When I saved the file again, after making some formatting changes, it saved a file called 2004EE00 onto my desktop. I am unable to move it to Trash, open it, or even Get Info.

What is this file, and how do I get rid of it?

First, try deleting it after you restart.
If that doesn’t work, you can delete it from the terminal:
Sudo rm (then drag the file from the Finder to the terminal window and drop it) <return>

You can try to download Unlocker. Here is one version for Mac.

The file seems to have taken it upon itself to be gone.

I did do a restart earlier for another reason. I don’t know if that had anything to do with it. I didn’t touch the file afterward.