Complex sentence: After mistakenly assuming that the smell was being caused by Gunter the penguin's flatulence, the Ice King realizes that his armpits, in fact, are the source of the smell, after taking a shower, he ponders aloud as to how he got so smelly.
Split into simpler sentences: After mistakenly assuming that the smell was being caused by Gunter the penguin's flatulence, the Ice King realizes that his armpits, in fact, are the source of the smell. After taking a shower, he ponders aloud as to how he got so smelly.