What it does
Assemble isn't a standard Magic keyword—it appears as part of the Contraption mechanic from the Unstable set, written as "Assemble [Contraption name]." When an effect tells you to assemble a Contraption, you put it from your separate Contraption deck onto one of your three "sprockets" (your assembly line), where it stays as an artifact that triggers based on which sprocket it's on.
The big point of confusion: Assemble and Contraptions are part of the Un- sets (silver-bordered/acorn cards), so they aren't legal in standard Commander. You need a dedicated Contraption deck alongside your library, plus a "Steamflogger" or similar card to actually assemble them.
In Commander, this only matters in casual, un-set-friendly playgroups. Confirm with your table beforehand, since most competitive or rules-strict pods won't allow acorn-bordered cards at all.
Iconic cards with Assemble
See all 1 →