Bizarre and Astounding
MUTATIONS!

There's an asteroid belt in the astroscape called the Asterband. But there's also a ring of comets that occasionally collide, break up, and send fragments flying towards the worlds of the astroscape, where they impact and cause some damage. But the impact isn't the biggest concern. The major factor is the radiation.

The comets are heavily irradiated with various types of radiation, and when they hit, they irradiate an area. If you go near the radiation, many things can happen. You could get sick. You could die. You could become horribly malformed. Or you could mutate in potentially beneficial ways.

Mutations can give you extra limbs, heighten your senses, imbue you with psionic powers, or dramatically increase physical or mental attributes.

Of course, they could take away limbs, reduce your sense, strip away psionic powers, or dramatically decrease physical or mental attributes.

Some are willing to take the risk, and hope to benefit.