Complex sentence: Mothra attempts to fight against him but is not strong enough, to stop him Mothra goes back in time to defeat Cretaceous King Ghidorah the first time he came to feed, which resulted in the extinction of the dinosaurs.
Split into simpler sentences: Mothra attempts to fight against him but is not strong enough. To stop him Mothra goes back in time to defeat Cretaceous King Ghidorah the first time he came to feed, which resulted in the extinction of the dinosaurs.