Upkeep Costs

[citanul]

Jotun Grunt has a cumulative upkeep cost of putting 2 cards in a graveyard from the game to the bottom of the library.
I was wondering if it was possible to put this cost on the stack, sacrifice Pernicious Deed (or any other form of removal for that matter) killing the Grunt but letting the triggers from the upkeep cost resolve.

[Skeggi]

Yes.

303.1. As the upkeep step begins, any abilities that trigger at the beginning of that upkeep step and any abilities that triggered during the turn’s untap step go on the stack. (See rule 410, “Handling Triggered Abilities.”) Then the active player gets priority and players may play spells and abilities.
Remember though, that Cumulative Upkeep reads:

502.13a Cumulative upkeep is a triggered ability that imposes an increasing cost on a permanent. “Cumulative upkeep [cost]” means “At the beginning of your upkeep, put an age counter on this permanent, then sacrifice this permanent unless you pay [cost] for each age counter on it.”
So, when the trigger of the upkeep resolves, its controller can still choose whether he'd like to pay it or not.

[citanul]

Thanks for the quick reply.