Undead and Concentration Checks

[Hanuman]

Do undead make concentration checks? Does something devoid of a con score make a concentration check?

[Jallorn]

Do undead make concentration checks? Does something devoid of a con score make a concentration check?

Short answer: Yes.

Longish answer: Only if it's not mindless. So, say, a vampire is subject to concentration checks. Mostly Con doesn't matter to an undead because they have immunities, however, anything related to Con that isn't mentioned under those immunities is as normal.

[Chilingsworth]

Yes. To do so, such creatures add their Charisma modifiers to the check.

[Hanuman]

Yes. To do so, such creatures add their Charisma modifiers to the check.

Thanks! `

[Shhalahr Windrider]

Yes. To do so, such creatures add their Charisma modifiers to the check.

If by “Such Creatures” you mean Undead, and not creatures with no Constitution in general. Substituting Charisma modifier for Constitution is a specific ability of the undead type. Other creatures without Constitution scores, such as Constructs would make Concentration checks without a +0 Con modifier.

Short answer: Yes.

Longish answer: Only if it's not mindless.

I don’t see anything that says mindless creatures cannot make Concentration checks. Of course, in most cases, mindless creatures cannot take actions that would require Concentration checks. But if something were to happen that allowed the creature to do so, they would be allowed to make an untrained Concentration check, just like they can make any other untrained checks. (Mindless creatures get no skill points, so all skill checks they make are untrained.)