Phyrexians are invading the whole Multiverse at once, and March of the Machine is representing that with battle cards, a new type of permanent card that can be attacked, like planeswalkers. The battles in this set are all Sieges, the first battle subtype.

Incubate is a new keyword action that always has a number next to it. To "incubate N" means to create an Incubator token that enters the battlefield with N +1/+1 counters on it. An Incubator token is a transforming double-faced token. Its front face is a colorless Incubator artifact with "{2}: Transform this artifact." Its back face is a colorless 0/0 Phyrexian artifact creature.