Complex sentence: But Metro Man shows up and chases Hal away while dying Megamind reveals he is actually Minion in holographic disguise (and only his armor is destroyed) and Metro Man is actually Megamind.
Split into simpler sentences: But Metro Man shows up and chases Hal away. While dying, Megamind reveals he is actually Minion in holographic disguise (and only his armor is destroyed) and Metro Man is actually Megamind.