Looks like I'll save it.....but consider it part of the emergency under-mattress stash. To answer your question Picasimus, we call this a star note because the last character of its serial number, typically a letter, has been replaced with a small green star (or asterisk if you prefer). This indicates that this bill was printed as part of a production run to replace bills that quality control has found to be defective in some way. Since no two bills can share a serial number, they use the star on the replacement. Google can tell you more, but that's the gist of it.
And like kingskid1611, I use mycurrencycollection.com to find out more information about the star notes.
I agree with DozerD, searching notes could be pretty fun....maybe I'll give it a go next time there are no halves to be had.