Calvin and Hobbes by Bill Watterson for December 08, 1987
Susis: Did you see we have a substitute teacher today? Calvin: Oh, no! That can only mean our real teacher went back to Saturn to report to her superiors! They're trying to subvert up little kids in our textbooks, telling us to turn in our parents when the saturnians attack! Earth will be rendered helpless! Susie: I think one of us has been eating too much paste in art class. Calvin: I'm too smart for 'em, though! I don't read my assignments!