Plot summary
In an experiment, a two-headed Martian scientist, who is invisible to Earthlings, gives vacuum-cleaner salesman and perennial loser Luther Dingle superhuman strength. After discovering his inexplicable powers, Dingle begins performing various feats of strength, from lifting statues to splitting boulders, and gains a great deal of publicity.
The two-headed Martian returns and is disappointed to see that Dingle is using his strength only for show. The Martian takes his strength away just as Dingle attempts to lift a building before a live television audience. Unable to make good on his claims or repeat any of his previous feats, Dingle becomes a laughingstock.
As the two-headed Martian scientist leaves, he meets two Venusians, who are also searching for a suitable Earthling for an experiment. The two-headed Martian scientist recommends Dingle and the Venusians gives Dingle super intelligence. Discovering his new powers, Dingle starts thinking aloud at an alarming rate and demonstrates incredible powers of prediction.
Credits
Adapted from Wikipedia contributors, Mr. Dingle, the Strong. Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.