: Return target white or black creature card from your graveyard to the battlefield. That creature gains "Cumulative upkeep
." If the creature would leave the battlefield, exile it instead of putting it anywhere else. (At the beginning of its controller's upkeep, that player puts an age counter on it, then sacrifices it unless they pay its upkeep cost for each age counter on it.)
If a permanent has multiple instances of cumulative upkeep, each triggers separately. However, the age counters are not connected to any particular ability; each cumulative upkeep ability will count the total number of age counters on the permanent at the time that ability resolves.