The inciting incident (catalyst) of a story is the event that sets the main character or characters on the journey that will occupy them throughout the narrative.
It Came Out of the Sky
Whoa, it came out of the skyLanded just a little south of MolineJody fell out of his tractorCouldn't b'lieve what he seen, ohLaid on the ground shookFearin' for his lifeThen he ran all the way to townScreamin', "It came out of the sky"Well, a crowd gathered 'roundAnd a scientist said it was marsh gasSpiro came to make a speechAbout raisin' the Mars taxVatican said, "Woe, the Lord has come"Hollywood rushed out an epic filmRonnie the Populist saidIt was a communist plotWhoa-ohOh, the newspapers cameAnd made Jody a national heroWalter and Eric said they'd put himOn a network TV showWhite House said, "Put the thing in the Blue Room"The Vatican said, "No, it belongs in Rome"Jody said, "It's mineBut you can have it for 17 million"Whoa, it came out of the skyLanded just a little south of MolineJody fell out of his tractorCouldn't b'lieve what he seen, ohLaid on the ground a-shakin'Fearin' for his lifeAnd then he ran all the way to townScreamin', "It came out of the sky"