Great one,
Hookbill!
I absolutely second
Legate's demand for more F&S appearances in the future.*
And
Lottie, if you're looking for a scientific explanation, my guess would be that FutureAlien's time-travels caused a rift in the continuum that allowed Fungoltch unt Shcmurt to cross over from their parallel universe into P&A's... but I suppose that makes far too much sense, and anyway, who really cares?
*(Personal note on why I like them so much: about twenty years ago, my best friend and me collaborated on a quasi-dadaistic conlang that looked and [presumably] sounded uncannily like the dialogues from F&S, only with less diacritics and non-Latin characters. If you think the phonology was weird, you don't want to hear about the semantics...)