edhseer Commander synergy, explained
Land
If you control two or more other lands, this land enters tapped.
static —
Add {W}.
activated {T} — adds 1 mana
This land becomes a 3/4 white Dragon creature with flying until end of turn. It's still a land.
activated {4}{W} — turns something into a creature
Causes: nothing.
Cares about: nothing.
a land enters the battlefield — 1,560 cards in the game can cause this (Cave of the Frost Dragon is one).
When Cave of the Frost Dragon enters:
199 other cards care about it too. These are the ones with the most connections.