The Howl and mutation

The Howl is known to cause all kinds of mutations, but as a general rule, the more extreme the mutation, the rarer it is for the afflicted to come out alive. All visible mutations have negative impacts socially, as they are viewed as a sign that the individual is a Grinning Cultist. No one exposed to the Howl gets only positive or neutral mutations, and almost all of the exposed become sterile. Only survivable negative mutations are noted here; presumably your dragonoid isn't going to die in a week.

All rarities are only referring to those mutations caused by the Howl; many of the mutations have alternate causes that occur naturally (eg., blindness and deafness are still natural occurrences, as are many genetic disorders common to modern humans).

This are not the only mutations that can occur, but do check in with ClyncyeRudje if you need help figuring out an unlisted mutation's rarity.

"Magic-based" mutations do not exist; all mutations should be at least loosely based in biology. Additionally, it is very rare for Cultists to come out of the Howl fertile; simply surviving alters their biology so drastically that their bodies either redirect all energy to survival or are made completely incompatible with other dragonoids.

If you have any questions, please comment with them.

Common Mutations

Positive/Neutral:
Longer horns
Minor marking changes
Small spinal ridge
Benign Tumors
Large scales/scutes
No scales, only skin

Negative:
Necrosis
Neuropathy (nerve pain)
Sense Alteration (eg., blindness, enhanced senses, weakened senses)
Brain chemical disturbances

Uncommon Mutations

Positive/Neutral:
Fur/hair tufts (usually on chest, limbs, and head)
Major marking changes
Additional horns
Horns/spines on joints
Glowing markings
Ears

Negative:
Organ disruption (eg., difficulty breathing, sudden inability to digest certain things)
Hemophilia (due to marrow alterations)
Epilepsy

Rare Mutations

Positive/Neutral:
Additional eyes (nonfunctional)
Additional limbs (nonfunctional/minimally functional)
Large scale fur/hair distribution
Any feathers
Fins

Negative:
Paralysis

Very Rare Mutations

Positive/Neutral:
Additional limbs (functional)
Additional eyes (functional)
Any wings
Heavy feathering
Increased/unaffected fertility
Extended life

Negative:
Exposed/visible organs (survivable variant)