Felix Finite
Felix Finite is a light-blue potion that induces a sense of irrational sadness upon the drinker. When ingested by those under the effects of Euphoria Elixir, or any sort of happiness elixir, it works as a counter-effect concoction. The liquid itself is rather cold to touch, and a complete vial of it will be enough to bring up a dying feel of sadness, so its use must be supervised by a capable healer.

Addicted patients have the need to ingest large amounts of happiness elixirs. Simply prohibiting them to get access to such elixirs generally leads to an increase of aggression and mental related trauma. The treatment with Felix Finite consists in providing the patient a modified happiness concoction, in order to reduce its effects gradually until the patients needs it no more. It is a less intrusive and gently manner to handle the addiction, preserving the mind and body of the patients.

Uses: Treatment of induced happiness addicted.
Side-Effects: If ingested without any sort of happiness elixir or charm in effect, symptoms such as excessive sadness, depression, sense of desperation and light sensibility might occur to the drinker.
Characteristics: Light-reflective blue color. Cold to touch.
Ingredients: Shrivelfig, dried mallowsweet leaves, water from the mouth of a stream near the peak of a mountain, mixed in an adamantine cauldron. After 2 hours brewing, the brewer must cast the spell Depressius at the concoction and let it rest for a day. Peppermint should be added in order to remove any chance of side-effects.

The Depressius Charm
Depressius is a charm that causes the feeling of dying sadness. It is also able to reveal to the person the image that causes more sadness to him/herself only. There isn't any sort of documented material concerning this spell, or any particular author described in tomes or manuscrits, or if it was ever used before the studies of Chase Armitage on Felix Finite potion.

Characteristics
Upon casting, this invisible spell will penetrate the mind of the target, forcing it to dig through his subconciousness and impose extreme sadness. The spell itself works on the opposite of Cheerio charm, and its side-effects and knowledge produced are quite benefical, even though its area of effect walks in a thick line between the common magic and dark magic.

The Incantation & The Hand Movement
The incantation must be uttered while having the most sad memory in your mind, with firm words. Depressius (dee-PREH-ssius). Flick your wand, upwards while speaking and downwards to your targets forehead. With a flick release the spell at it.

Depressius and the Dark Arts
A philosofical discussion should be started, since this Charm works to cause something bad to the target. Impose sadness, cause it, even though in minor proportions, should it make Depressius a Dark Spell? I must say depends. Depends on what are your goals by casting such spell. If your target is someone under excess of cheerio charm, or if you are brewing an antidote, that requires neutralization of the euphoria senses, it would not fit the category of a Dark Spell.

Still, should you be willing to inflict sadness, just to cause harm to your target, be that even yourself, Depressius must be taken as a Dark Spell. The spell by itself is harmless, though high doses of it will cause temporary or even permanent damage to the mind of the targeted being, such as depression, dependancy, feeling of emptiness.