From NWN2Wiki
// Returns Item property Monster on hit apply effect property. You must specify
// the property that you want applied on hit. There are some properties that
// require an additional special parameter to be specified. The others that
// don't require any additional parameter you may just put in the one. The
// special cases are as follows:
// ABILITYDRAIN:nSpecial is the ability to drain.
// constant(IP_CONST_ABILITY_*)
// DISEASE :nSpecial is the disease that you want applied.
// constant(DISEASE_*)
// LEVELDRAIN :nSpecial is the number of levels that you want drained.
// integer between 1 and 5.
// POISON :nSpecial is the type of poison that will effect the victim.
// constant(IP_CONST_POISON_*)
// WOUNDING :nSpecial is the amount of wounding.
// integer between 1 and 5.
// NOTE: Any that do not appear in the above list do not require the second
// parameter.
// NOTE: These can only be applied to monster NATURAL weapons (ie. bite, claw,
// gore, and slam). IT WILL NOT WORK ON NORMAL WEAPONS.
itemproperty ItemPropertyOnMonsterHitProperties(int nProperty, int nSpecial=0);
