edhseer Commander synergy, explained
Land
Add {C}.
activated {T} — adds 1 mana
Until end of turn, your opponents and creatures your opponents control with hexproof can be the targets of spells and abilities you control as though they didn't have hexproof.
activated {1}, {T} — grants a keyword
Causes: nothing.
Cares about: nothing.
a land enters the battlefield — 1,560 cards in the game can cause this (Detection Tower is one).
When Detection Tower enters:
199 other cards care about it too. These are the ones with the most connections.