Complex sentence: In the end, Mr. Incredible and Frozone finally defeat the Underminer, making his machine go haywire, fly into the sky, and come down hard on the Gilgenbot's head, causing a giant explosion that destroys the Gilgenbot and kills the Underminer.
Split into simpler sentences: In the end, Mr. Incredible and Frozone finally defeat the Underminer, making his machine go haywire, fly into the sky, and come down hard on the Gilgenbot's head. This causes a giant explosion that destroys the Gilgenbot and kills the Underminer.