Complex sentence: Ron was wearing a Zorpox costume to infiltrate HenchCo's Evil Trade Fair when he was turned evil by a device called the "Attitudinator", a helmet-like device which swapped his inner evil with Dr Drakken's, who was the last previous wearer.
Split into simpler sentences: Ron was wearing a Zorpox costume to infiltrate HenchCo's Evil Trade Fair when he was turned evil by a device called the "Attitudinator". This helmet-like device swapped his inner evil with Dr Drakken's, who was the previous wearer.