Ugin's Labyrinth
Land
Oracle Text
Imprint — When this land enters, you may exile a colorless card with mana value 7 or greater from your hand.
{T}: Add {C}. If a card is exiled with this land, add {C}{C} instead.
{T}: Return the exiled card to its owner's hand.
Watch Out
This card uses a replacement effect ('as [it] enters' or 'enters with') to modify how the permanent enters. This is NOT a triggered ability — it can't be responded to, and effects like Panharmonicon or Torpor Orb don't affect it.
This card's ability triggers when it enters the battlefield, not when it's cast. Effects that double ETB triggers (like Panharmonicon) work here. Countering the spell prevents the creature from entering, so the ETB won't fire.
If this card's activated ability produces mana and doesn't target, it's a mana ability. Mana abilities resolve immediately without using the stack — opponents can't respond to them. However, abilities that target (even if they produce mana) aren't mana abilities.