Calvin the Human Insect first appeared in the 5/12 through 5/13 1986 story arc, where Calvin had inexplicably skrunken to the size of an insect, and acquired the proportionally high strength of one. Calvin the Human Insect seemed rather pleased of his condition, cheerfully discovering his newfound strength by catapulting peas with a spoon at dinnertime. Later he was seen very slowly turning a single page of a school textbook. This was analogous to Calvin respectively playing with his food and doing his homework with difficulty.
Calvin the Human Insect reappeared in a later, single weekday comic, where he was seeking medical treatment for his condition. To contact his family, he wrote "Help I'm a bug" on the typewriter to alert his family. This attitude was far removed from that of the previous appearance, in which he expressed no such concern.