School of Simulacra
The study of wizardry is ancient, stretching back to the earliest mortal discoveries of magic. It is firmly established in the worlds of D&D, with various traditions dedicated to its complex study. The most common arcane traditions in the multiverse revolve around the schools of magic. Wizards through the ages have cataloged thousands of spells, grouping them into categories called schools. In some places, these traditions are literally schools; a wizard might study at the School of Illusion while another studies across town at the School of Enchantment. In other institutions, the schools are more like academic departments, with rival faculties competing for students and funding. Even wizards who train apprentices in the solitude of their own towers use the division of magic into schools as a learning device, since the spells of each school require mastery of different techniques.
Many view the snow as a byproduct of cold weather and a portent of colder times to come, but wizards have long known the potential of snow and ice as special components for their spells. With the right words and gestures, a particularly long ritual, and a potent illusion, a mass of snow or ice can be molded into the exact likeness of a creature, creating a lifelike doppelganger known as a simulacrum.
This spell has such versatility and such usefulness, an entire school of magical thinking has sprung up around its use: the School of Simulacra. Its practitioners are called simulators, and are always, except in rare circumstances, accompanied by simulacrums of their own creation.
Starting at 2nd level, your study of simulacra has taught you the amazing skill of copying almost anything you watch. When a creature you can see makes an ability check, attack roll, or saving throw, you can use your reaction to record the result of that roll and the type of roll it was (an ability check or saving throw using a particular ability score, or a melee, ranged, or spell attack roll). When you make a roll of the same type, you can replace your roll with this recorded roll. You must choose to do so before the roll, and you can replace a roll in this way only once per turn.
You can use this feature a number of times equal to your Intelligence modifier (a minimum of once). You regain all expended uses when you finish a long rest.
Starting at 6th level, when you finish a long rest, you can create an illusory duplicate of yourself or another willing creature in your company. The duplicate is a creature, partially real and formed from ice or snow, and lasts for 24 hours before it collapses into a melting heap. It can take actions and otherwise be affected as a normal creature. It appears to be the same as the original, but it has one-fourth the creature’s hit point maximum and is formed without any equipment. The duplicate cannot cast spells or make more than one attack on each of its turns. Otherwise, the illusion uses all the statistics of the creature it duplicates.
The simulacrum is friendly to you and creatures you designate. It obeys your spoken commands, moving and acting in accordance with your wishes and acting on your turn in combat. The simulacrum lacks the ability to learn or become more powerful, so it never increases its level or other abilities, nor can it regain expended spell slots.
This simulacrum can’t be repaired and reverts to snow if it is reduced to 0 hit points.
By 10th level, you can even copy spells by sight. When you see a wizard spell cast, you can fix its form in your mind for up to 24 hours. You can only have one such spell memorized at a time. While this spell is in your mind, you can copy it into your spellbook without having a written copy of the spell. Doing so requires the same amount of gold, but takes half the amount of time.
Starting at 14th level, you have become a master of crafting and controlling simulacra. Casting the simulacrum spell and repairing damaged simulacra requires half as much time and gold. In addition to your minor simulacrum, you can have up to two active duplicates created by the simulacrum spell at one time.