If you're saying "Who??," Arnie Pye in the Sky is Springfield's traffic-copter newsman with the perfect closed-nose news voice. ("Look out at the corner of 12th and Main because I'm going to be sick!") Arnie is hilarious as a second-rate reporter with an inferiority complex and a chip on his shoulder; he's jealous of Kent Brockman and so desperately wants his job. (In fact, Arnie once got to take over the anchor's desk, whereupon he instantly dropped the nasally newscaster voice and adopted the smooth tones of trustworthiness.)
Arnie Pye's best moment (fleeting as it was) was an early sign of the budding rivalry. Flying above Homer's disaster with a van full of kids, Kent asks him "How are the children, Arnie?" to which he snaps "I can't see through METAL, Kent!"--yes, it loses something on paper, but old Arnie Pye spits it out with such venom, such acidic hatred, you get years of professional and personal contention in those seven syllables. Kudos to Dan Castellaneta's greatest vocal performance. We want more Arnie Pye in the Sky and we want him now.