A.11.1- The ability is written as "Cumulative upkeep -
A.11.2- This ability means "At the beginning of your upkeep, put a
cumulative upkeep counter on this permanent. Then sacrifice this
permanent unless you
A.11.3- It is a triggered ability (see Rule A.4) that triggers at the start of your upkeep. [CompRules 2001/07/23 - 502.13a]
A.11.4- If a permanent has multiple cumulative upkeep abilities, each one triggers separately, but each one counts all cumulative upkeep counters. For example, if a permanent has two instances of "Cumulative Upkeep - Pay one life", then both would trigger. When the first trigger resolves, you add one counter and pay the life total (1 if no counters were there before). When the second trigger resolves, you add a second counter and pay the life total (2 if no counters were there before). [CompRules 2001/07/23 - 502.13b]
A.11.5- If a new cumulative upkeep is added by adding text to a card, such as with Mana Chains, then a new cumulative upkeep ability is added to the card. Each cumulative upkeep ability triggers separately. [CompRules 2001/07/23 - 502.13b]
A.11.Ruling.1- The result of adding counters is that the cost to be paid is one times the cost the first time it is paid, two times the cost the second time, three times the cost the third time, and so on. See Rule A.11.2. [CompRules 2001/07/23 - 502.13a] For example, if a card has "Cumulative Upkeep: {B} and 2 life", you pay {B} and 2 life on the first upkeep, {B}{B} and 4 life on the next upkeep, {B}{B}{B} and 6 life on the next upkeep, and so on. [D'Angelo 1998/02/03]
A.11.Ruling.2- If cumulative upkeep is not paid for some period of time because the permanent is not in play or was temporarily changed so that it no longer had a cumulative upkeep, the cumulative upkeep tracking is not reset because the cumulative upkeep counters are not removed. Payment resumes as soon as it applies. [D'Angelo 1999/05/01]
A.11.Ruling.3- Cumulative upkeep is not reset if the permanent changes controllers, because the counters are not removed. [D'Angelo 1999/05/01]
A.11.Ruling.4- Permanents which count their last paid cumulative upkeep count the number of cumulative upkeep counters on the card and multiply by the cost per counter. [D'Angelo 1999/05/01]
A.11.Ruling.5- This ability is put on the stack (see Rule T.2) at the beginning of upkeep. If the permanent leaves play before this ability resolves, you still have to resolve it. Of course, you can just decide not to pay and there will be nothing to sacrifice. But you can also choose to pay if you really want to. [D'Angelo 1999/05/01]
A.11.Ruling.6- If the cumulative upkeep cost somehow changes between the time the ability is placed on the stack and when it resolves, use the cost at the time it was put on the stack. [DeLaney 2000/01/13]