Cast any other instant card from your hand by paying its mana cost.
Holding priority, cast Spelljack by paying {3}{U}{U}{U} targeting the instant.
Thousand-Year Storm triggers, creating at least one copy of Spelljack that is targeting the original Spelljack.
Resolve the first copy of Spelljack, countering the original Spelljack and exiling it with the ability to cast it for free from exile.
All remaining copies of Spelljack fail to resolve due to having no legal targets.
Cast Spelljack from exile without paying its mana cost, targeting the instant cast in Step 1.
Repeat from step 3.

Infinite magecraft triggers

Infinite storm count

Thousand-Year Storm

Spelljack

Cast any other instant card from your hand by paying its mana cost.
Swarm Intelligence triggers, choose not to create a copy of the instant.
Holding priority, cast Spelljack by paying {3}{U}{U}{U} targeting the instant remaining on the stack.
Swarm Intelligence triggers, creating a copy of Spelljack that is targeting the original Spelljack.
Resolve the copy of Spelljack, countering the original Spelljack and exiling it with the ability to cast it for free from exile.
Cast Spelljack from exile without paying its mana cost, targeting the instant cast in step 1.
Repeat from step 4.

Swarm Intelligence

Cast Bonus Round by paying {1}{R}{R}, causing you to copy any instant and/or sorcery spell you cast this turn.
Cast any other instant card from your hand by paying its mana cost.
Bonus Round triggers, copying the instant.
Holding priority, cast Spelljack by paying {3}{U}{U}{U}, targeting the instant.
Bonus Round triggers, creating a copy of Spelljack that is targeting the original Spelljack.
Resolve the copy of Spelljack, countering the original Spelljack and exiling it with the ability to cast it for free from exile.
Cast Spelljack from exile without paying its mana cost, targeting the instant cast in step 1.
Repeat from step 5.

Bonus Round

Cast any other instant or sorcery card from your hand by paying its mana cost.
Chandra and Displacer Kitten triggers.
Resolve the Displacer Kitten trigger, blinking Chandra.
Resolve the Chandra trigger, creating a copy of the instant or sorcery.
Holding priority, cast Spelljack by paying {3}{U}{U}{U}, targeting the instant or sorcery cast in step 1.
Chandra and Displacer Kitten triggers.
Resolve the Displacer Kitten trigger, blinking Chandra.
Resolve the Chandra trigger, creating a copy of Spelljack that is targeting the original Spelljack.
Resolve the copy of Spelljack, countering the original Spelljack and exiling it with the ability to cast it for free from exile.
Cast Spelljack from exile without paying its mana cost, targeting the instant or sorcery cast in step 1.
Repeat from step 6.

Combos with "Spelljack"