Hey, it's the first (and possibly only) appearance of Chibi Felicity! While there's very few characters that DIDN'T appear in this comic at some point, Felicity showing up for no apparent reason was never in doubt.
Prior to this strip, Felicity had debuted in January 2003 in the original "Basil Flint P.I." series. She swiftly became an instant favorite and went on to star in her own series just a few months later, when T Campbell's GraphicSmash network was launched in September of that same year. She would later return to her parent series and pop back up AGAIN when Andie got her own series in 2005.
Felicity is basically a webcomic nomad, is what I'm saying.