Lou is deaf, so it would have to be a prannk TTY
"Lou suffered an ear infection and permanently lost 80% of his hearing."
http://en.wikipedia.org/wiki/Lou_FerrignoSo...
ARNOLD [trying to disguise his voice] : I'm very sorry, Mr. Ferrigno. It is my sad duty to inform you that your mother was found murdered in her home this morning.
LOU : What?
ARNOLD [speaking louder] : It is my sad duty to inform you that your mother was found murdered in her home this morning!
LOU : My mother was what?
ARNOLD [shouting] : She's dead!
LOU: My mother is dead?!
ARNOLD [shouting] : Ya! Dead! Get it?
LOU [distraught] : Oh my God! Mama! And she wanted to call me yesterday! But I insisted on charging her $4.99 for the first minute and $0.99 for each additional minute!
ARNOLD [breaking into laughter] : Ha ha ha! I got you, Lou!
LOU : What?
ARNOLD [shouting] : I got you, Lou! This is Arnold! I was playing a joke on you!
LOU : Arnold?
ARNOLD [shouting] : Ya, that's right! I fooled you into thinking your mother was dead! Ha ha ha!
LOU [whimpering] : That wasn't nice, Arnold.
ARNOLD : You don't win 7 Mr. Olympias by being Mr. Nice Guy! Ha ha ha!