Duplicatus Plantis is a plant that can duplicate humans, though if you duplicate a human in this plant they are sure to double-cross their host. This plant is found in Vault 14. Boomer, Brady, and Mikayla all duplicated themselves.
Duplicatus Plantus copied Boomer and Brady. The two copies began taking over the kingdom, trapping the real kings in Vault 14. However, they used Duplicatus Plantus to make lots of copies of themselves and they retreated to their room.
When Brady and Boomer attempted to break into the vault, they discovered a copy of Mikayla. (The Trouble With Doubles)