Art Mirror

Art Mirror allows the caster to learn any spell they decide as long as they have seen it before and know its name and all it's rules and limitations.

First, the caster needs to get a book, notebook, papyrus or any paper-esque material/object where something can be written; when the user sees a spell be casted by any other creature, they need to find a way to learn its real name and all its real rules and limitations, afterwards they have to write everything down in the material component of the spell. This doesn't take space in the Known Spells/Memorized Spells of the caster.

The caster can then use the spell regardless of class limitation (meaning if the spell is, for example, just for paladins and the caster is a sorcerer, they can still use it), the spell keeps all the other limitations it originally has, its original duration and its original range. The written spell can only be used up to its 2nd scalation, for example: if a spell begins at level 1 and scales until 6th level, the caster of Art Mirror can only use the written spell until 3rd level; in the other hand, if a spell begins at level 5 and scales until level 9, the caster can only use it up to its 7th level.

In order to use the written spell, the caster has to spell the name while reading it from where is written, not necessarily out loud, it can be whispered. The casting takes one bonus action to read the spell and one action to use the written spell, if the written spell spends one bonus action, that action is added to the caster's round (One bonus action is used to read the spell, one action is used to use the written spell and one extra bonus action is used for the bonus action of the written spell).

After having been used five times, the spell will vanish from the material where it was written and in order to gain it again, the Art Mirror user needs to see it once more be performed by someone else, even if the caster still remembers the name, rules and limitations.

There's no limitation to the numbers of spells that can be written, it depends on the space available in the material component. If a book has only 4 blank pages, then only 4 spells can be written, but if the books has 200 blank pages, then 200 spells can be written.