What is a morale penalty?

[Rattlesnake Dick]

My friend wants to use the trait Low Blow from Agents of Evil, and it says specifically

Agents of Evil wrote:

When targeting a good-aligned creature with a spell or spell-like ability... that imposes a morale penalty

What is a morale penalty?

Bless gives a morale bonus to allies, but bane is an untyped penalty to enemies.

What kind of Morale penalties are there that fit this trait RAW or RAI?

[Fuzzy-Wuzzy]

Penalties are not typed so I'd call this an outright error. Pretend the word "morale" isn't there.

Getting Started wrote:

Penalty: Penalties are numerical values that are subtracted from a check or statistical score. Penalties do not have a type and most penalties stack with one another.

[Nyerkh]

Yeah, that's not a thing that exist. As Fuzzy said, penalties are untyped.

You kind of need something though, just applying the trait to any penalty might be a bit strong.
Then again Fear, Emotion and Mind-affecting, make up a lot of the penalty spells anyway, iirc.
Still, as a houserule I'd probably base the trait on some or all of those descriptors, rather that the non-existent Morale Penalty. Maybe not Fear.

[fearcypher]

Morale penalties exist int he rules, and they don't apply to undead. I don't know any other effects of them though.

[Fuzzy-Wuzzy]

Writers occasionally screw up and assign a type to a penalty. They're wrong to do so, though. :)

[blahpers]

fearcypher wrote:

Morale penalties exist int he rules, and they don't apply to undead. I don't know any other effects of them though.

Undead are immune to mind-affecting effects; that gives them immunity to "morale effects", which are a bit fuzzily defined apart from morale bonuses.

There is no such thing as a morale penalty in textbook Pathfinder. Penalties are not typed. A penalty from a "morale effect" would be ignored because of the nature of the effect itself, not because of the "type" of penalty. (Shame that they didn't unify bonuses and penalties in this respect, but here we are.)