Complex sentence: However, Killer Moth was accidentally exposed, alongside of his pet moths, to the powerful chemical, turning him into a gigantic, mutated, deadly moth, and forced everyone on the gang to follow Penguin's orders.
Split into simpler sentences: However, Killer Moth was accidentally exposed, alongside of his pet moths, to the powerful chemical which turned him into a gigantic, mutated, deadly moth. In this form, Killer Moth forced everyone on the gang to follow Penguin's orders.