Would a threnodic hold monster affect undead?

[MorganS]

The description of the thredonic metamagic feat says,

"Benefit: This feat only works on mind-affecting spells. A threnodic spell affects undead creatures (even mindless undead) as if they weren’t immune to mind-affecting effects, but has no effect on living creatures."

Since hold monster affects one living creature, would a threnodic hold monster affect nothing?

It's the "but has no effect on living creatures" that makes the hold monster case fuzzy, because it implies that the "living creature" restriction on the original spell is also altered.

Maybe looking at this in template terms would help. It seems that a "thredonic hold dragon" spell would affect an undead dragon, thus common sense says a "thredonic hold monster" should affect undead.

[cappadocius]

MorganS wrote:

Since hold monster affects one living creature, would a threnodic hold monster affect nothing?

It's the "but has no effect on living creatures" that makes the hold monster case fuzzy, because it implies that the "living creature" restriction on the original spell is also altered.

The trick here is to look at hold person, since hold monster says it functions like that spell. hold person makes no claim to living or non-living; it is simply a mind-affecting spell. The only reason hold monster specifies any living creature is specifically so it doesn't work on undead, and the whole point of a threnodic spell is to cast mind-affecting spells on undead.

Threnodic Spell says it has no effect on living creatures specifically so you don't try to use it on Oozes, which are also immune to mind-affecting spells.