edhseer Commander synergy, explained
Instant — Trap
Mana cost: {4}{G}{G}
If a creature spell you cast this turn was countered by a spell or ability an opponent controlled, you may pay {0} rather than pay this spell's mana cost.
Look at the top seven cards of your library. You may put a creature card from among them onto the battlefield. Put the rest on the bottom of your library in any order.
on-cast —
Causes: put a creature onto the battlefield.
Cares about: nothing.
an instant is cast — 3,931 cards in the game can cause this (Summoning Trap is one).
When Summoning Trap is cast:
427 other cards care about it too. These are the ones with the most connections.
a nontoken creature enters the battlefield — 18,448 cards in the game can cause this (Summoning Trap is one).
When a creature enters thanks to Summoning Trap:
23 other cards care about it too. These are the ones with the most connections.
a creature enters the battlefield — 19,800 cards in the game can cause this (Summoning Trap is one).
295 other cards care about it too. These are the ones with the most connections.
anything enters the battlefield — 26,499 cards in the game can cause this (Summoning Trap is one).
21 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 (Summoning Trap is one).
When Summoning Trap is cast:
6 other cards care about it too. These are the ones with the most connections.