Jackal, Genius GeneticistHow it works & interactions with other cards

The Genetic Algorithm

Jackal, Genius Geneticist has a triggered ability that checks the mana value of any creature spell you cast against Jackal's current power. If they match, you get a non-legendary copy of that creature spell on the stack. Importantly, the copy is not 'cast,' so it won't trigger Jackal's ability a second time, but it will enter the battlefield as a token.

Step-by-Step Resolution

When you cast a creature spell, Jackal's ability checks the spell's mana value. If it matches Jackal's power, the ability goes on the stack above your spell. First, the ability creates a copy of the creature spell; this copy resolves first and becomes a token. After the copy is created, Jackal receives a +1/+1 counter. Finally, your original creature spell resolves and enters the battlefield.

Precise Calculations

Because Jackal puts a +1/+1 counter on himself after copying a spell, his power increases every time the ability successfully triggers. This means you must cast creatures with increasingly higher mana values to keep the chain going. If Jackal's power changes in response to the trigger, the ability still uses the mana value of the spell as it was cast to determine if it should have triggered, but it checks Jackal's power at the time the trigger resolves.

When to Deploy the Geneticist

Jackal is most effective in decks with a 'curve' of creatures that match his growing power. Starting at 2 power, he naturally looks for 2-drop creatures, then 3-drops, and so on. He is also a threat himself, as Trample ensures the +1/+1 counters he accumulates can push through damage directly to your opponent.

Interaction examples

Starting the Chain

Jackal, Genius GeneticistLlanowar Elves

If Jackal's power is currently 1 (perhaps through a debuff or effect), and you cast Llanowar Elves (mana value 1), Jackal triggers. You receive a token copy of Llanowar Elves, and then Jackal gains a +1/+1 counter, becoming a 2/2.

The Perfect Curve

Jackal, Genius GeneticistBirds of Paradise

Jackal, Genius Geneticist is normally a 2/2. If you cast a creature with mana value 2, the ability triggers. However, if you cast Birds of Paradise (mana value 1) while Jackal is at 2 power, the ability will not trigger. You must match his power exactly to get the copy.

Double Production

Jackal, Genius GeneticistCopy

When you cast a creature spell that matches Jackal's power, the 'Copy' token enters the battlefield first. Because Jackal specifies the copy isn't legendary, you can even copy other legendary creatures without having to sacrifice one to the 'Legend Rule.' Jackal then grows larger, preparing for your next, more expensive creature spell.