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'Whenever a creature enters, its controller sacrifices a creature or land of their choice.
'At the beginning of your upkeep, you may put a charge counter on this artifact. {T}: You may put a creature card with mana value equal to the number of...
{T}, Exile this artifact: Add {U}. When you next cast an instant or sorcery spell this turn, copy that spell. You may choose new targets for the copy.
'Choose target spell or permanent that's red or green. Its owner puts it on their choice of the top or bottom of their library.
'Remove all counters from all permanents and exile all tokens.
'Ripple 4 (When you cast this spell, you may reveal the top four cards of your library. You may cast spells with the same name as this spell from among...
'{U}, Sacrifice this artifact: Return target creature to its owner's hand.
{1}, Sacrifice this artifact: Draw a card.
'{4}{W}: Return another target creature you control to its owner's hand.
As long as The Aetherspark is attached to a creature, The Aetherspark can't be attacked and has "Whenever equipped creature deals combat damage during your turn, put that many loyalty...
'{U}, Sacrifice this artifact: Return target creature to its owner's hand.
{1}, Sacrifice this artifact: Draw a card.
'Trample
Whenever this creature enters or attacks, you get {E} (an energy counter) for each creature you control.
Pay {E}: This creature gets +1/+1 until end of turn.
Haste
Whenever a creature an opponent controls dies, put a +1/+1 counter on Yahenni.
Sacrifice another creature: Yahenni gains indestructible until end of turn.