Cieran Locale, Shadow Hold

If you cast a spell with a mana cost including Phyrexian mana, you may tap Cieran Locale,
Shadow Hold. If you do so, treat up to three Phyrexian mana of the spell cost as paid and put
a nightmare counter on this land.
If Cieran Locale, Shadow Hold has eight or more nighmare counters on it, transform it.
"The Shadow-Hold was once seen to be an ordinary mountain-pass ..."—The Lands of Cier - World Map