You gain the ability to cast necrotic cyst spells by growing a cyst of your own.
Prerequisites: Caster level 1st, Knowledge (religion) 2 ranks.
Benefit: You grow an internal cyst of undead flesh called a mother cyst. The cyst may be noticeable as a discolored swelling on your skin, if desired. The mother cyst is slightly painful, but otherwise isn’t harmful. The mother cyst grants you access to a selection of cyst-related spells listed below. You cast these spells like any other spell you can cast, once you host a mother cyst (if you are a caster who prepares spells, you can prepare all necrotic cyst spells without referring to a spellbook, as if you had the Spell Mastery feat for each such spell).
Necrotic Cyst Spells: 1st—necrotic awareness; 2nd—necrotic cyst, necrotic scrying; 3rd—necrotic bloat; 4th—necrotic domination; 5th—necrotic burst; 6th—necrotic eruption; 7th—necrotic tumor; 8th—necrotic empowerment; 9th—necrotic termination.
Normal: A creature without this feat cannot cast necrotic cyst spells.
Source: Libris Mortis, page 28.