Homer: Who are you?
Newton: Homer, I'm your guardian angel. I've assumed the form of
someone you'd recognize and revere: Sir Isaac Newton.
Homer: Sir Isa-who?
Newton: Oh, very well. [transforms himself]
Homer: [gasps] Colonel Klink! Did you ever get my letters?
Klink: I'm not actually Colonel Klink, I'm just assuming his form.
Homer: Hee hee hee! Did you know Hogan had tunnels all over your camp?
-- The chance of a lifetime,
"The Last Temptation of Homer"