Complex sentence: Feeling badly for Piglet, Pooh, Eeyore and Tigger decide to throw a fright-free "Hallo-wasn't" party for Piglet, who flees from his home when he mistakes the costumed three for a monster.
Split into simpler sentences: Feeling badly for Piglet, Pooh, Eeyore and Tigger decide to throw a fright-free "Hallo-wasn't" party for Piglet. Piglet flees from his home when he mistakes the costumed three for a monster.