For the same reason I ate a relleno for dinner: it got in my head on the drive home and I couldn't get it out of there.
Regyptian Strut, AKA Variant Processional March. The YouTube description says, "The Big Note -- Frank Zappa Alchimiste -- Live Jazz á Vienne ed. 2009", which I believe is German for "Make it go fast, in and out, magical pig."