Simulacrum was a type of constructed digital individuals that could be created by either the Machines, humans or Exiles. (similar to the idea of clones).
Redpills, who belong to the Coder talent tree have the ability to summon some types of Simulacrum, known as Daemons. Some Simulacrum can be made to appear in someone else's likeness, such as the one that was based on Morpheus. In the case of the Morpheus simulacrum, dead tissue samples of the late Morpheus was used in thje construction of his cloned simulacrum.