The Power stone

At the begining of your upkeep, remove all power counters from The Power stone and then add X
power counters to The Power stone where X is
the number of Infinity stones you control.
{t}, Remove 1 power counter: Spells you cast cost {1} less to cast until end of turn.
{t}, Remove 3 power counters: Create a copy of
target instant, sorcery or activated ability. You
may choose new targets for the copies.
{t}, Remove 5 power counters: You can cast spells and activate abilitys without paying their