Complex sentence: Osborn was the main antagonist in the first "Spider-Man" film; he later made cameo appearance in "Spider-Man 2" (2004) and "Spider-Man 3" (2007) as a halluincation in Harry's head.
Split into simpler sentences: Osborn was the main antagonist in the first "Spider-Man" film. He later made cameo appearances in "Spider-Man 2" (2004) and "Spider-Man 3" (2007) as a halluincation in Harry's head.