It's a single map for the First Encounter. You might think it's about bats, but it really isn't.
Die Fledermaus by Bruce W. Anderson is a single map for the First Encounter. It's about bats or something. Other than the funky title (which does not seem to refer to anything in particular; certainly not to the Spear mission packs) there's not much out of the ordinary here, just a fairly extensive map.
===CREDITS===
Bruce W. Anderson and his megacorporation called NothingWare. The author provides contact info: spock (at) torino.ohionet.org, as well as his FTP server: Torino.ohionet.org but unsurprisingly, the latter is offline nowadays