With the release of Spelljammer for D&D 5th Edition, I decided to break out the second AD&D Spelljammer module Skulls & Crossbows. I'm looking at it particularly with quick conversion in mind, but also for story and general usefulness. The fourth adventure in the book is called "Pirate-wyrm."
Less an adventure than an encounter, this is a scenario designed to happen at any time during a larger campaign. The story, such as it is, involves a radiant dragon attacking the PC's ship. That's the story.
As with Flying colours, this kind of scenario is actually really useful for two reasons:
Should the PCs defeat but not kill their foe, there's a possibility that the dragon attempts to buy her life with promises of treasure from her lair. Her lair is in an asteroid, which I think could make for a really interesting exploration side quest. For instance, what if this lair was something that this dragon found but did not make, and there turns out to be a secret door into a dungeon delve?
For conversion purposes, it's important to know that there is no such thing as a radiant dragon in any official 5e material, not even Fizban's Treasury. I have a few thoughts on replacements.
The most obvious replacement is any dragon you please, with the special Unusual nature trait applied. This trait makes any terrestrial creature Wildspace-compatible.
You could alternately refer to Boo's Astral Menagerie for a creature. The fact that this dragon burrowed a lair into an asteroid and is clearly evil makes me think that a Lunar Dragon is a reasonable replacement. Lunar Dragons burrow through rock quickly, and they dwell in Wildspace, so it makes sense.
However, the Solar Dragon from Boo's Astral Menagerie is also a strong candidate. These are neutral-aligned dragons and they're immune to radiant damage, and dwell in Wildspace.
A young Lunar or Solar dragon is CR 7 or 8, and this encounter is proposed for levels 6-8, so that's spot on. The encounter takes place within an asteroid field (or at least the dragon can lead them into an asteroid field if they're giving chase) so there's potential for some very important manouever checks in order to avoid flying rock damage. Of course, Spelljammer 5e embarrassingly has no manouever mechanic for its ships (no, that's seriously true). In my ship combat rules, I impose manoeuver checks against a DC equal to a ship's beam. I have no idea how much a ship's beam influences manoeuverability in real life, but if I believe that ships can fly in outer space then I can believe that the ship's beam is the single most significant factor in how quickly it can dodge an asteroid.
One thing missing from any dragon's stat block is an idea raised in the book: the ability to tail-swipe an asteroid at the PC ship. It's essentially just a giant boulder throw, but for a space dragon.
With these added threats, you have flexibility to adjust the danger of the encounter, plus you get experience running ship-against-creature combat.
The next adventure is called "Bloody vikings," and I'll cover it in my next Spelljammer post.