Mishra's Self-Replicator - DOM-223 R PLST

Whenever you cast a historic spell, you may pay {1}. If you do, create a token that's a copy of this creature. (Artifacts, legendaries, and Sagas are historic.)
It has witnessed history's most significant events, one incarnation after another.
rare
Artifact Creature — Assembly-Worker
From the Magic: The Gathering set The List.