Fusion Rot

Fusion Rot is a condition that can affect users of fusion magic. The risk associated with fusion, the magical combination of the caster and another lifeform (generally plant or animal) is extremely high and thus there are few fusion users who have not experienced this is some form.

Causes

When fusion magic is performed, the caster must have a strong sense of their human self in order to separate from the fused being completely once the spell is no longer needed. In order to do this, the caster must 'find' their own being within the fused creature they have become and return those 'pieces' of themselves to one whole. When this does not happen properly, Fusion Rot is the result. This most often occurs when a caster attempts to fuse with something that is too high for their abilities. As such, most remain using only plants or insects/small lizards.

Symptoms

There are both physical and mental symptoms associated with Fusion Rot, which can appear separately or congruently. 
Physical symptoms include retaining the physical characteristics of whatever the caster fused with. These can be feathers, scales, changed eye or hair color, claws, rearranged bone structure, etc. 
Mental symptoms are similar, but involve the mindset of what was fused with. Generally, this is seen in diminished mental capacity from a vegetative state to a purely animalistic one.

Treatment

Most instances of Fusion Rot are mild and the symptoms will disappear on their own after a given amount of time, hours to months depending on the severity. In order to increase the speed of the process, some fusion users will attempt to physically remove feathers, scales, etc. This is not recommended as it is painful and can lead to infected wounds. 
Mental treatment is more difficult and involves immersing the caster in their standard life. This has been said to speed recovery, but the results are mixed at best.

Prognosis

In general, those afflicted recover on their own when given time. If the physical symptoms become permanent, the caster generally learns to work around them in most cases. However, the most damaging prognosis is seen in the mental effects. When the caster is unable to return to themselves, they can become feral or enter into a coma. Those that experience this are either sheltered by other users (or friends and family) or, in extreme cases where they are deemed dangerous to themselves or others, killed.

Prevention

In order to prevent Fusion Rot, most users of fusion magic insist on extensive training with simple beings before moving on to more complex lifeforms. They also recommend long meditations to learn about oneself so that 'piecing' together the original identity is easier.

Cultural Reception

Most of the public sees Fusion Rot as merely a side effect of standard, although complex, magical practice. Those who bear permanent effects are not seen as lesser or greater than others. Any who have suffered severe mental effects are mixed. Some believe they were stupid for attempting to fuse with something outside of their abilities. Others take pity on them.

Type

Magical

Origin

Magical

Rarity

Common