Name: The Cloning Enchantment
Incantation: Sibi Duplicare (To double in English)
Movements: I don't know that many spells, but maybe Swish Up > Swish Down > Swish Left > Swish Right > Jab (It's a complex spell with a high backfire)
Year: 6-7
Effect: Become invisible for varying seconds, while invisible 4-5 npc's of you will spawn in the place you disappeared at, causing a distraction. More of a fun spell, but can be useful for escapes.
Backfire: Wasn't sure, maybe something like random teleportation or the items in your inventory start making useless copies that disappear after some time?