edhseer Commander synergy, explained
Instant
Mana cost: {3}{U}{U}{U}
Counter target spell. If that spell is countered this way, exile it instead of putting it into its owner's graveyard. You may play it without paying its mana cost for as long as it remains exiled.
on-cast —
on-cast —
Causes: counter a spell, exile a spell, a spell leaves the battlefield.
Cares about: nothing.
anything is exiled — 2,497 cards in the game can cause this (Spelljack is one).
an instant is cast — 3,931 cards in the game can cause this (Spelljack is one).
When Spelljack is cast:
427 other cards care about it too. These are the ones with the most connections.
anything is cast — 31,128 cards in the game can cause this (Spelljack is one).
When Spelljack is cast:
5 other cards care about it too. These are the ones with the most connections.