Complex sentence: A reassured Bart decides to go to a baseball game with Walt, who removes his small shoes to show his long feet folded inside, revealing himself to be Sideshow Bob.
Split into simpler sentences: A reassured Bart decides to go to a baseball game with Walt. However, Bart's initial instincts prove right when "Walt" removes his small shoes to show his long feet folded inside, revealing himself to be Sideshow Bob.