When Wormwood is struck by lightning is SW or RoG, he is lit on fire, even when wearing an Eyebrella or similar lightning-resistant clothing. This issue is not present in Hamlet. Here is an image for proof (I spawned a Thunderbird to make the lightning strike):
Steps to Reproduce
Go to RoG or SW, equip lightning-resistant clothing, and watch Wormwood light on fire.
This issue has not been confirmed by a developer yet.